- labium
- lacunar
- lagoon
- lamella
- lanceolate
- larva
- lateral
- lateral line
- lateral rib
- lateral spine
- lectotype
- life history
- life-cycle
- ligament
- lip
- lip angle
- lip belly
- lip flap
- lip gutter
- lip rim
- lip shoulder
- liver
- lobe
- Loc.
- local
- lock angle
- lock area
- lock link
- lock rib
- lock system
- lock tubercles
- longitudinal
- lumen
- lunate