| California cuebid |
| Canape |
| Cansino |
| Cappelletti |
| Captain |
| Captaincy |
| Card-showing double |
| Carryover scores |
| Cheaper minor |
| Cheapest bid |
| Checkback Stayman |
| Chico two diamonds |
| Chinese finesse |
| Churchill style |
| Cipher bid |
| Clarac slam try |
| Clear a suit |
| Clubs for takeout |
| Colorful cuebid |
| Combination finesse |
| Come-on, come-on signal |
| Comic Notrump overcall |
| Command bid |
| Competitive double |
| Conglomerate major raises |
| Constructive raises |
| Control asking bids |
| Control maintenance |
| Controlled psychics |
| Controls |
| Convenient minor |
| Cooperative double |
| Copenhagen convention |
| Count signals |
| Courtesy bid |
| Cover cards |
| Covering honors |
| Crash |
| Crashing honors |
| Crisscross raise |
| Crowhurst |
| Cuebid |
| Cuebid as a light takeout |
| Cuebids in opponents suit |
| Cuebids to show controls |
| Culbertson asking bid |
| Culbertson four-five notrump |
