Labour (Labor) Day (or May Day)
Ladder Diagram (Relay Ladder Diagram)
Laminar Flow (or Streamline Flow)
Laws of Science (Scientific Laws)
LCDM (Lambda Cold Dark Matter)
Legitimation or Legitimisation
Leprosy or Hansen's disease (HD)
Liberalisation (or Liberalization)
LIBOR (London Interbank Offered Rate)
Licensed process Design Package
Life Cycle Cost Analysis (LCCA)
Lighting and Distribution Panel Schedule
LIGO (Laser Interferometer Gravitational-Wave Observatory)
LIGO Scientific Collaboration (LSC)
Limited Liability Company (LLC)
Limiting Oxidant Concentration (LOC)
Liquid Based Solar Heating System
Liquid To Liquid Heat Exchanger
Lithium Ferrophosphate Battery (or LFP Battery)
Lithium Sulphur Battery (Li-S Battery)
Lithium-Ion Battery (Li-I Battery)
LNG (Liquefied Natural Gas) Project
LNG (Liquefied Natural Gas) Storage Tank
LNG Membrane Containment System
LNGC (Liquefied Natural Gas Carrier)
Local Distribution Company (LDC)
Look Ahead Schedule (Window Schedule)
LOPA (Layers of Protection Analysis)
Loss of Load Probability (LOLP)
Low Emissivity Windows & (Window) Film
Low Voltage Disconnect Hysteresis
LRG (Liquefied Refinery Gases)
LTIFR (Lost Time Injury Frequency Rate)
LTIIR (Lost Time Injury Incidence Rate)