C.

C. or c. may refer to:
 * 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
 * Circa, abbreviated as c. (or ca., circ., cca, and cc.) a Latin word meaning "about" or "around"
 * Abbreviation c. meaning "chapter" in legal citation
 * Prefix c/c. (and cc/cc.) meaning "column(s)" as in-source-locator in old citations (example: "c130")