- deciduous
- deep scattering layer
- demersal
- dental formula
- denticle
- denticulate
- dermal
- desert
- desmosomes
- detergency
- diapause
- dichotomous
- diffuse
- diffusion
- dilated
- dimorphic
- diploid
- disjunct
- dispersal
- dissected
- dissection
- distad
- distal
- distributed
- diurnal
- divergence
- DNA
- domestic
- dorsal
- dorsal fin
- dorsal hump
- dorsal ridge
- dorsum
- dune