1. Abounding in or bordered by rocky cliffs or scarps
   "the rock-ribbed coast of Maine"
   - rockbound 
2. Tradition-bound and obstinately opinionated
   "rock-ribbed republican"
   - die-hard

See also: inflexible, rough, unsmooth

• family Dicamptodontidae
• family Dicksoniaceae
• family Dicranaceae
• family Didelphidae
• family Dilleniaceae
• family Dinornithidae
• family Diodontidae
• family Diomedeidae
• family Dioscoreaceae
• family Dipodidae
• family Dipsacaceae
• family Dipterocarpaceae
• family Discoglossidae
• family doctor
• family Doliolidae
• family Dracunculidae
• family Drepanididae
• family Dromaeosauridae
• family Droseraceae
• family Drosophilidae
• family Dryopteridaceae
• family Dugongidae
• family Dytiscidae
• family Ebenaceae
• family Echeneidae