- labelling
- labelling technique
- laboratory coat
- Lamb shift
- lambda particle
- lambert
- lambertian reflector
- lamellar
- laminar separation
- lamp replacement
- lamphouse
- Lande factor
- landing skid
- Langevin function
- lap weld
- Larmor precession
- Laserjet
- lateral vibration
- lateral vibrations
- Laue pattern
- leader
- leader line
- leakage resistance
- laser machining
- laser printing
- laser spectroscopy
- lasercard
- latency
- lateral magnification
- lathe operator
- launching fiber
- launching fibre
- laxator
- leak rate
- LED display
- legendre polynomial
- length contraction
- lens barrel
- lens hood
- lens movement
- lens stop
- lavender print
- layout drawing
- leaching coefficient
- leak test
- leak tightness
- leaping weir
- leather case
- lens case
- lens flares
- lens mount
- lens-cap
- lenticular vein
- lepton number
- level difference
- level holding
- Liapunov exponents
- lichtenberg figure
- lieberkuhn reflector
- leather bellows
- lens aperture
- lens coating
- lens flange
- lens panel
- lens vertex
- lepton
- leptonic
- level displacement
- level shift
- lever rule
- lid
- lift
- lifting table
- lifting truck
- light cell
- light energy
- light exposure
- light guide
- light meter
- light modulator
- light output
- light pipe
- light radiation
- light source
- light unit
- light value
- light yield
- light-positive
- light-sensitive
- lightbox
- lightening hole
- lighting stand
- limit cycle
- limit setting
- limiter
- linac
- line profile
- line speed
- line stretcher
- line width