- Centaurea imperialis
- Cotula coronopifolia
- cape marigold
- China aster
- Consolida ambigua
- Cheiranthus asperus
- cosmea
- Chrysanthemum leucanthemum
- Cheiranthus cheiri
- candytuft
- cross infection
- cowpie
- cattle plague
- catarrhal fever
- chronic wasting disease
- costiasis
- canine chorea
- camelpox
- chorea
- creeps
- Cupid's disease
- Cupid's itch
- condensation pump
- capital of liechtenstein
- childbirth
- cytosmear
- cytologic smear
- Cox_2 inhibitor
- chemical phenomenon
- common corn salad
- capital of malta
- corroborative
- cardiac valve
- cardiopathy
- carnivorous bat
- carl van doren
- carl clinton van doren
- costal groove
- coccidioidomycosis
- coccidiomycosis
- Chartism
- characteristic root of a square matrix
- commodore vanderbilt
- cornelius vanderbilt
- chouse
- cobwebby
- chitterlings
- chitlins
- chance variable
- capital of the united states