C
| "Cabbaging" | Term for stealing |
| "Camp canard" | False report believed by many in camp |
| "Carte de Visite" | Photograph on a small card |
| "Cashier" | Usually dishonorable dismissal from army |
| "Chicken guts" | Officer's gold braiding on his cuff |
| "Chief cook and bottle washer" | Person capable of doing many things |
| "Chin Music" | Term for conversation |
| "Clink" | Jail or prison; originates from a prison in London on Clink Street |
| "Company Q" | Term for the sick list |
| "Conscription" | To be drafted, not volunteered |
| "Contrabands" | Fugitive slaves who sought protection behind Northern lines |
| "Coosh" | Term for hard tack to describe when it was soaked in water and fried in bacon grease to make it edible |
| "Copperhead" | Northerner with Southern sympathies |
| "Cracker line" | Line of transportation of food supplies |
| "Creeper" | Soldier's frying pan used early in the war |