C.

C. or c. may refer to:
 * Circa, abbreviated c., meaning "approximately", usually in reference to dates
 * Century, sometimes abbreviated as c. or C., a period of 100 years
 * Cent (currency), abbreviated c. or ¢, a monetary unit that equals $1/100$ of the basic unit of many currencies
 * Caius or Gaius, abbreviated as C., a common Latin praenomen
 * Abbreviation c. meaning "chapter" in legal citation