- luminous fungi
- luminous influence
- luminous plant
- lumisterin
- lumisterol
- lumphy structure
- lunar periodicity
- lunate
- lung
- lung sac
- lungworm
- luteal hormone
- lutein
- lutein cell
- luteinization
- luteinizing hormone
- luteotrophic hormone
- lyase
- lycophore
- lycopin
- lycopods
- lycopsida
- lye
- lymph
- lymph circulation
- lymph gland
- lymph heart
- lymph nodule
- lymphagogue
- lymphatic circulation
- lymphatic node
- lymphatic system
- lymphoblast
- lymphocyte
- lymphocyte transformation
- lymphocytoblast
- lymphocytotoxin
- lymphoid cell
- lymphoid tissue
- lymphoidocyte
- lymphokine
- lymphopoiesis
- lynx
- lyoenzyme
- lyophilic colloid
- lyophilizate
- lyophilization
- lyophobic bond
- lyophobic colloid
- lyotropic series