P Wave

P&I Clubs (Protection and Indemnity Club)

P&ID (Piping & Instrumentation Diagram)

P&ID for Fire Water Ring Main

P2P (Peer to Peer)

P50 (and P90, Mean, Expected and P10)

PAB (Pre-Assembled Building)

PAC (Programmable Automation Controller)

Pacemaker

Package

Packaged Equipment

Packaging

Packing

Packing List (Shipping List or Packing Slip)

Packing Slip

Pact

Pad

PADD (Petroleum Administration for Defence District)

Paddle Mixer

Paging Service

PAH (Polycyclic Aromatic Hydrocarbon)

Paid Up Lease

Paint

Painting

Palladium (Pd)

Pallet

Panama Canal

Pandemic

Panel

Panel and Rack Layout

Panel Radiator

Panel Study

Panel Survey

Panemone

Paper Mill

PAR (Pre-Assemble Rack)

Parabolic Dish (or Parabolic Reflector)

Parabolic Trough System

Paraffin (CnH2n+2, Alkane)

Parallel

Parallel Connection

Parameter

Parametric Model

Paramount Warranty

Pardon

Parent Company

Parental Leave

Parenteral

Pareto Chart

Pareto Efficiency

Pareto Principle (or 80/20 Rule)

Paris Agreement

Parliament

Part Time Employment/ Work

Partial Oxidation

Partial Pressure

Participant

Participate

Particle

Particle Size (or Grain Size)

Particle Size Distribution (PSD)

Particular

Particulate

Particulate Material

Particulate Matter (PM) or Particle Pollution

Partitioning

Partner

Partnership

Parts per Billion (ppb)

Party

Pascal (Pa)

Passivation

Passivator

Passive

Passive Bribery

Passive Equipment

Passive Solar (Building) Design

Passive Solar Heater

Passive System

Passive/ Natural Cooling

Paste

Paste Paint

Pasteurisation

Pasture

PAT (Portable Appliance Testing)

Patch

Patent

Paternalistic Leadership

Paternity Leave

Path

Pathogen

Pathway

Patina

Pattern

PAU (Pre-assembled Unit)

Pause

Pave

Paving Plan and Detail

Pay as you go (PAYG) Plan

Pay to Play Politics

Payback Period

Payload

Payment

Payment of Delay Penalty

Payments in Kind

Payout

Payroll

Payroll Burden

PCS (Process Control System)

PDF (Portable Document Format)

PDP (Process Design Package)

PE (Professional Engineer)

Peak

Peak Clipping

Peak Load (or Demand)

Peak Oil

Peak Oil Demand

Peak Power

Peak Power Current

Peak Shaving

Peak Shifting

Peaking Hydropower

Peat

Peck

PED (Pressure Equipment Directive)

Peeling

Peer

Peer Economy (or Peer to Peer (P2P) Economy)

Peer Review

Pegged Currency

Pellet

Pellet Stove

Pelton Turbine (or Wheel)

Penetrate

Penetration Rate

Pension Plan (or Scheme)

Penstock

Penta Resin 

Pentane (C5H12)

Pentanes Plus

People

PEP (Project Execution Plan)

Per Capita

Per Diem

Percentage

Percentage Yield

Percentile

Perception

Perchlorate

Percolate

Percolation

Perennial

Perfect

Perfect Competition

Perfect Storm

Perforate

Perform

Performance

Performance Appraisal

Performance Assessment

Performance Assurance

Performance Audit

Performance Based

Performance Bond

Performance Factor

Performance Guarantee

Performance Guarantees Statement

Performance Indicator

Performance Measure

Performance Test

Performance Test Procedure

Peril

Perimeter Heating

Period

Period Group (or Family)

Periodic Table

Periodicity

Periodontology (or Periodontics)

Peripheral

Peristaltic Pump

Permanent

Permanent Installation

Permeability

Permeable

Permeameter

Permeance

Permeation

Permission

Permissive

Permit

Permit to Work

Permittivity (e or er e0)

Permittivity (e or er e0)

Peroxide

Perpetual Bond

Persian Gulf Country

Persist

Persistence

Persistent Organic Pollutants (POPs)

Person

Personal Data

Personnel Cost

Personnel Monitoring Device

Perspective

Perspiration

PERT (Program Evaluation Review Technique)

Pertain

Pest

Pesticide

Petition

Petrochemical

Petrochemical Plant

Petrography

Petrol

Petroleum

Petroleum Chemistry

Petroleum Coke

Petroleum Extraction

Petroleum Process

Petroleum Reserve

Petroleum System

Petrology

PFD (Process Flow Diagram)

PFP (Passive Fire Protection)

pH

pH Meter 

PHA (Process Hazard Analysis)

Phantom

Pharmaceutical

Pharmacogenomics

Phase

Phase Change

Phase Change Material

Phencyclidine (PCP)

Phenol (C6H5OH)

Phenolic Resin

Phenolphthalein (C20H14O4)

Phi-factor

Philosophy

PHMSA (Pipeline and Hazardous Materials Safety Administration)

Phosphate (PO4)3−

Phosphating

Phosphoric Acid (H3PO4)

Phosphoric Acid Fuel Cell (PAFC)

Phosphorus (P)

Photobiological Hydrogen Production

Photochemical Air Pollution

Photochemistry

Photocurrent

Photoelectric

Photoelectric Cell

Photoelectric Effect

Photoelectrochemical Cell

Photoelectrolysis Hydrogen Production

Photoemission

Photogalvanic Process

Photogrammetry

Photometry

Photon

Photophobia

Photosynthesis

Photovoltaic (Conversion) Efficiency

Photovoltaic (PV)

Photovoltaic (PV) Cell

Photovoltaic (PV) Effect

Photovoltaic (PV) Generator

Photovoltaic (PV) Module

Photovoltaic (PV) Panel

Photovoltaic (PV) System

Photovoltaic Device

Photovoltaic-Thermal (PV/T) Systems

PHP (Hypertext Preprocessor)

Phrase

Physical

Physical Activity

Physical Constant

Physical Deterioration

Physical Explosion

Physical Hazard

Physical Inventory

Physical Model

Physical Pollution

Physical Property

Physical Vapor Deposition

Physiology

Pick

Pickling

Pickling Solution or Fluid

Pico-

Pictogram

Pie Chart (or Circle Chart)

Piece

Piece Rate

Piecework

Piezoelectricity

Pig

Pig Equipment

Pigging

Pigment

Pigment Volume

Pigouvian Tax

Piling Layout

Piling Specification

Pillar

Pilot Test

PIM (Pre inspection Meeting)

PIMS (Process Information Management System)

Pinch

Pinch Valve

Ping

Pinhole

Pink Tide

Pint

Pipe

Pipe Fitting

Pipe Rack

Pipe Ram

Pipe Schedule

Pipe Size

Pipe Spool

Pipe Spool Drawing

Pipe Stretch

Pipe Support

Pipe Support Spring Register and Calculation

Pipe Support Selection

Pipe Supports Design Detail

Pipe Wall Thickness

Pipeline

Pipeline Capacity

Pipeline Engineering

Piping

Piping Arrangement Drawing

Piping Engineering

Piping General Arrangement Drawing

Piping Material

Piping Material Specification

Piping Material Take-offs (MTOs)

Piping Specification

Piping Stress Analysis

Piping System

Piracy

Piston

Piston Compressor (or Reciprocating Compressor)

Piston Pump

Pit

Pitch

Pitch and Lead

Pitch Control

Pitot Tube

Pitting

Pitting Factor

Pivot

Pivotal

Pixel

Place

Place of Work

Placebo Effect

Placement

Plague

Plain English

Plaintiff

Plan

Plan B

Planck Constant (h, or Planck's Constant)

Plan-Do-Check-Act or Adjust (PDCA) Approach

Plane

Planet

Planetary

Planned Progress

Planning

Plant

Plant Air

Plant and Buildings Lighting Layout Drawing

Plant Cable Tray and Cable Routing Layout

Plant Completion Checklist

Plant Condensate

Plant Layout

Plant Operation

Plantation

Plasma

Plastering

Plastic

Plastic Deformation

Plasticiser

Plasticity

Plate

Plate Heat Exchanger

Plateau

Platform

Platform Economy

Platinum (Pt)

Plausibility

PLC (Programmable Logic Controller)

Plead

Pleasure

Plenish

Plenum

Pliable

PLM (Product Lifecycle Management)

Plot Plan

Plug

Plug Flow Digester

Plug Flow Reactor (PFR)

Plug Valve

Plug-in Hybrid Electric Vehicle (PHEV)

Plume

Plunge

Plunger Pump

Plutonium (Pu)

Plywood

PM (Project Manager)

PMC (Project Management Consultant)

PMI (Positive Material Identification)

PMI (Project Management Institute)

PMS (Power Management Solutions)

Pneumatic

Pneumatic Test

Pneumonia

Pnictogen

PO (Purchase Order)

Podcast

Point

Point Estimation

Point of Law

Point Source of Pollution

Poison

Poisson's Equation

Polar

Polar Bond

Polar Molecule 

Polarisation (or Polarization)

Polarisation Cell

Polarisation Resistance

Polarised Potential

Polarity

Pole

Policy

Policy Reform

Policymaker

Polish

Polished Joint

Polite

Political

Political Corruption

Political Risk

Politics

Poll Tax

Pollen

Pollutant

Pollution

Pollution Abatement

Pollution of Poverty

Pollution Prevention

Polonium (Po)

Polychlorinated Biphenyls (PCBs)

Polycondensation

Polycrisis

Polycrystalline Silicon

Polycrystalline Silicon Solar Cell (p-Si) or Multi-Crystalline Silicon Solar Cell (mc-Si)

Polycyclic Aromatic Hydrocarbon (PAH)

Polyester (PET)

Polyethylene (PE, (C2H4)n)

Polyisoprene

Polymer

Polymer Plug

Polymerisation (Polymerization)

Polyol

Polyprotic Acid

Polystyrene (PS, (C8H8)n)

Polyurethane

Polyvalent

Pond

Pool Fire

Pooling

Poppet Valve

Popularity

Population

Population at Risk

Pore

Porosity

Porosity Unit

Porous

Porous Media

Porphyrias

Port

Portable Building

Portal

Portfolio

Portfolio Investment

Portfolio Standard

Portfolio Theory

Portland Cement

Portmanteau (or Portmanteau Word)

Position

Positioner

Positive

Positive Displacement Compressor

Positive Displacement Pump

Positive Sum Game

Positivity

Positron

Possession

Possibility

Possible Reserve

Post Traumatic Stress

Postal Rule

Postcode

Pot Life

Potable Water

Potash

Potassium (K)

Potassium Chloride (KCl)

Potency

Potential

Potential Change Notice (PCN)

Potential Energy

Potential Explosion Site (PES)

Potentiodynamic

Potentiostat

Pound (lb or £)

Pound per Square Inch (Psi)

Pound Per Square Inch Absolute (psia)

Pound Per Square Inch Gauge (Psig)

Pour Point

Poverty

Powder

Power

Power Coefficient

Power Conditioning

Power Conditioning Equipment (or Power Conditioner)

Power Conversion Efficiency

Power Distribution One line for Instrumentation and Control System

Power Distribution Schedule for Instrumentation and Control System

Power Factor (PF)

Power Failure

Power of Attorney (POA)

Power Outage

Power Plant

Power Purchase Agreement (PPA)

Power Tower

Power Transmission Line

PPE (Personal Protection Equipment)

PPB (Parts per Billion)

PPI (Payment Protection Insurance)

ppm (parts per million)

PQ (Pre-Qualification)

PRA (Prudential Regulation Authority)

Practical

Practical Approach

Practice

Pragmatic

Prandtl Number (Pr)

Praseodymium (Pr)

PRCI (Pipeline Research Council International)

Pre Start-up Safety Review (PSSR)

Pre-Award Meeting

Pre-commissioning (PC)

Pre-commissioning and Commissioning Manual

Pre-fabrication

Pre-FEED

Pre-paid

Precaution

Precedence

Precedence Diagram Analysis

Precedent

Precipitate

Precipitation

Precipitation Reaction

Precise

Precision

Precursor

Predatory Pricing

Predecessor

Predetermine

Predict

Predictability

Predicted Environmental Concentration

Predicted Yield

Prediction

Predictive Maintenance

Predominant

Predominant Wind Direction

Preference Share

Preferential Weld Corrosion (PWC)

Preferred Definition

Preliminary

Premise

Premises

Premium

Premium Supplement

Prepare

Preparedness

Prepayment

Prescribe

Prescription

Prescriptive Requirement

Present

Presentation

Preservation

Preservation Work

Preserve

Pressure

Pressure Drop

Pressure Piling

Pressure Relief Valve (PRV)

Pressure Safety Valve (PSV) or Pressure Relief Valve (PRV)

Pressure Test

Pressure Vessel

Pressurisation (or Pressurization)

Pressurisation (Pressurization) Testing

Presurvey

Pretrial Conference

Prevailing Wind

Prevalence

Prevent

Preventative Maintenance (PM)

Prevention

Preventive Action

Preventive Measure

Preventive or Preventing Fouling

Preventive Safeguard

Price

Price Cap

Price Devaluation

Price Discrimination

Price Effect

Price Index

Price Regulation

Price Relative

Price Reversal Test

Price Similarity Index

Prima Facie

Primary Battery

Primary Commodity

Primary Containment

Primary Data

Primary Energy Consumption

Primary Energy 

Primary Extraction

Primary Income

Primary Insurance Amount (PIA)

Primary Management System

Primary Market

Primate

Primavera Schedule

Prime

Prime Contractor

Primer

PRINCE2

Principal (Obligor)

Principal Component Analysis (PCA)

Principal Repayment Schedule

Principle

Prior Breakdown Method (Construction Price Indices)

Priority

Privacy

Privacy Statement/ Policy

Private

Private Company

Private Corporation

Private Equity Fund (PEF)

Private Internal Rate of Return

Private Sector

Privatisation

Privilege

Pro Bono

Pro Forma

Pro Forma Invoice

Pro Rata

Proactive

Probabilistic Imputation

Probabilistic Risk Assessment (PRA)

Probability

Probability Based Disclosure

Probability of Failure (POF)

Probable Reservoir

Probation

Probe

Probit

Problem

Problem Solving

Procedure

Process

Process & Operational Control Description

Process Alarm & Trip Schedule

Process Approach

Process Area

Process Area Plot Plan

Process Audit

Process Certification

Process Datasheet (Data Sheet)

Process Datasheets for Instrumentation

Process Datasheets for Main Equipment

Process Design

Process Design Calculation

Process Engineering

Process Equipment

Process Equipment List

Process Excellence

Process Facility

Process Flow Diagrams (PFDs), Utility Flow Diagrams (UFDs) and Heat & Material Balances (HMBs)

Process Gap Analysis

Process Innovation

Process Life Cycle

Process Media

Process Medium

Process Safety

Process Safety Competency

Process Safety Culture

Process Safety Engineering

Process Safety Information (PSI)

Process Safety Management (PSM)

Process Safety Management System

Process Safety System (PSS)

Process Severity

Process Simulation Report

Process-Based Quality Management System

Processing Gain

Processing Loss

Procure

Procurement

Procurement Management

Procurement Work Process (Cycle)

Produce

Producer’s Price

Product

Product Audit

Product Innovation

Product Manager

Product Specification

Product Stewardship

Production

Production Capacity

Production Cost

Production Engineering

Production Sharing Agreement (PSA)

Productivity

Productivity Index (PI)

Profess

Profession

Professionalism

Profile

Profilometer

Profit

Profit Margin

Profit Sharing

Profitability

Profitability Index (PI)

Profits of Export Monopoly

Profits of Import Monopoly

Progradation

Programmable Electronic System (PES)

Programmable Controller System (PC System)

Programmable Thermostat

Programmatic

Programme (Program)

Programme Evaluation

Programme Management (Program Management)

Programme Manager (Program Manager)

Programme Sustainability

Programmable Controller

Progress

Progress Measurementation

Progress Payment

Progress Reporting

Progressive Cavity Pump

Progressive LSTK (Lump Sum Turn Key) Contract

Prohibit

Prohibition Notice

Project

Project Acceptance Criteria

Project Achievement

Project Administrator

Project Administration

Project Alignment Meeting

Project Alliancing (or Alliance Contracting)

Project Assessment

Project Assumption

Project Baseline

Project Baseline Document

Project Baseline Schedule

Project Baseline Work Process

Project Business

Project Calendar

Project Close-out

Project Control

Project Control Structure

Project Controlling

Project Cost

Project Cost Accounting

Project Definition

Project Definition Rating Index (PDRI)

Project Director

Project Due Diligence

Project Duration

Project Execution

Project Financing

Project Goal

Project Health Check (PHC)

Project Initiation

Project Integration Management

Project Intelligence

Project Interface

Project Life Cycle (or Project Management Life Cycle)

Project Management

Project Management Programme (Program)

Project Management Body of Knowledge (PMBOK)

Project Mission Statement

Project Monitoring

Project Objective

Project Organisation

Project Phase

Project Planning

Project Portfolio

Project Portfolio Management (PPM)

Project Protocol

Project Quality Management

Project Roadmap

Project Schedule

Project Screening

Project Stakeholder

Project Summary Schedule (Level 2 Schedule)

Project TF (Task Force) Organisation

Project Vision

Projected

Projected Benefit Obligation (PBO)

Projection

Prolific

Prolong

Promethium (formerly prometheum, Pm)

Promise

Promissory Note

Promote

Promotion

Prompt

Pronunciation

Proof

Proof Test

Propagate

Propagating Factor

Propane (C3H8)

Propane Dehydrogenation (PDH)

Propellant or Propellent

Propeller (Hydro) Turbine

Propene (C3H6)

Property

Property Income

Property Right

Proportion

Proposal

Proposal Process

Proposal Opportunity Assessment

Proprietary

Proprietary Information

Proprietor

Propriety

Propylene (C3H6)

Propylene Oxide (C3H6O or CH3CHCH2O)

Prospect

Protactinium (formerly protoactinium, Pa)

Protect

Protection

Protective Coating

Protective System

Protein

Proteomics

Protocol

Proton

Proton Exchange Membrane or Polymer Electrolyte Membrane (PEM) Fuel Cell

Protonation

Prototype

Prove

Proven Reservoir

Provide

Provider

Provision

Provisional Acceptance (PA)

Provisional Acceptance Certificate (PAC)

Provisional Sum

Provisioning

Provitamin

Proximate Analysis

Proximate Cause

Proxy

PS (Performance Standard)

PSC (Production Sharing Contract)

PSDS (Product Safety Data Sheet)

Pseudoplastic

Psi (Pound per square inch)

Psia (Pound Per Square Inch Absolute)

Psig (Pound Per Square Inch Gauge)

Psychosis

Psychrometer

Psychrometrics

PT (Liquid Penetrant Testing)

PTSD (Post-Traumatic Stress Disorder)

Public

Public Company

Public Corporation

Public Debt

Public Disclosure

Public Enterprise

Public Good

Public Health Emergencies of International Concern (PHEIC)

Public Network

Public Official

Public Private Partnership (PPP)

Public Relations (PR)

Public Sector

Public Service Obligation (PSO)

Public Utility

Publication

Puff

Pulp

Pulse Echo

Pulse Width Modulated (PWM) Wave Inverter

Pulverized Coal Combustion

Pump

Pump Cavitation

Pump Priming

Pump Submergence

Punch List

Punctuality

Pungent

Purchase

Purchase Requisition (or PO Requisition)

Purchased Goodwill

Purchaser’s Price

Purchasing Power Parity (PPP)

Pure Basic Research

Pure Price Index

Pure Substance 

Purge Gas

Purging

Purification

Purified Water

Purity

Purpose

Pursuit

Push Technology

Putrefaction

PV (Present Value)

PVC (Polyvinyl Chloride)

PWHT (Post Weld Heat Treatment)

Pyranometer

Pyrolysis

Pyrophoric Gas (NFPA 55)

Python