- cyclophorus lingua
- cyclorama
- cyclostomata
- cycnoches
- cyclothymic disorder
- cyder
- cydippea
- cygnus buccinator
- cydippidea
- cygnet
- cygnus atratus
- cydippida
- cydonia
- cygnus
- cygnus columbianus
- cygnus columbianus bewickii
- cygnus columbianus columbianus
- cygnus olor
- cylindrical lining
- cylindricality
- cylinder
- cylindricalness
- cyma
- cylindric
- cylix
- cylinder lock
- cylinder head
- cymatium
- cyma reversa
- cymatiidae
- cyma recta
- cymbal
- cymbidium
- cymbid
- cymling
- cymric
- cymograph
- cymru
- cynara cardunculus
- cynara
- cymry
- cynewulf
- cynically
- cynipid wasp
- cynical
- cynara scolymus
- cynipid gall wasp
- cynipidae
- cynocephalidae
- cynips