China 
Africa 
- Lethal dose
- Lethality
- Lethargy
- Leucine zippers
- Leucite
- Leuco dyes
- Leucogranite
- Leucoxene
- Leukemia
- Leukocyte esterase
- Leukocytosis
- Leukoencephalopathy
- Leukopenia
- Leukoplakia
- Leukotriene b4
- Leukotrienes
- Levan
- Levansucrase
- Levator ani
- Levator scapulae
- Levees
- Level crossings
- Level flight
- Level of consciousness
- Level of detail
- Level of measurement
- Level of service
- Level sensor
- Level set
- Level shifter
- Level-set method
- Leveling effect
- Levelling
- Levenshtein distance
- Lever
- Lever action
- Lever rule
- Lever-action
- Leverage
- Levi-Civita connection
- Levi-Civita symbol
- Levinson recursion
- Levocetirizine
- Levofloxacin
- Levoglucosan
- Levopimaric acid
- Levothyroxine
- Levulinic acid
- Lewis acids
- Lewy bodies
- Lewy body
- Lewy body dementia
- Lewy body dementias
- Lex
- Lexical analysis
- Lexical decision task
- Lexical resources
- Lexicographic order
- Leyden jars
- Leydig cells
- Lgr5
- Lherzolite
- Li
- Li-fi
- LiTFSI
- Library
- Library catalog
- Libsvm
- License plate
- Lichen
- Lichen planus
- Licorice
- Lidar
- Lidocaine
- Lie algebra
- Lie bracket
- Lie derivatives
- Lie groups
- Liebig condenser
- Liesegang rings
- Life cycle
- Life cycle thinking
- Life expectancy
- Life history
- Life safety code
- Life support
- Life tables
- Life-cycle assessment
- Life-cycle cost analysis
- Lift
- Lift coefficient
- Lift-induced drag
- Lift-off
- Lift-to-drag ratio
- Lifting bag
- Lifting equipment
- Lifting gas
- Lifting scheme
- Lifting-line theory
- Liga
- Ligament
- Ligamenta flava
- Ligamentum flavum
- Ligand efficiency
- Ligand-gated ion channels
- Ligands
- Ligase chain reaction
- Ligases
- Ligation
- Light
- Light beam
- Light bulb
- Light chains
- Light cones
- Light crude oil
- Light field
- Light field camera
- Light metals
- Light meter
- Light pollution
- Light rail
- Light reflectance value
- Light scattering by particles
- Light soaking
- Light stage
- Light switch
- Light transport
- Light valve
- Light-dependent reactions
- Light-emitting diode
- Light-field camera
- Light-gas gun
- Light-harvesting complexes
- Light-second
- Light-water reactor
- Light-weight processes
- LightGBM
- Lightfastness
- Lighting
- Lighting control system
- Lighting design
- Lightning
- Lightning arresters
- Lightning detection
- Lightning strikes
- Lightpaths
- Lights
- Lightweight protocols
- Lightweighting
- Lignan