C78

C78 or variation, may refer to :


 * Ruy Lopez chess openings ECO code
 * Secondary malignant neoplasm of respiratory and digestive organs ICD-10 code
 * Medical Examination of Young Persons (Non-Industrial Occupations) Convention, 1946 code
 * K&R C (Kernighan and Ritchie C), C programming language standard released in 1978, sometimes called C78, the original widespread version of C
 * Caldwell 78 (NGC 6541), a globular cluster in the constellation Corona Australis
 * C-78 Bobcat, a 1954 military aircraft
 * HMAS Kanimbla, WWII Australian armed merchant cruiser
 * ARM Zamora, Mexican Navy ship, an Auk-class minesweeper originating in WWII
 * Mauser C78 "zig-zag", single-action revolver handgun
 * 78th edition of Comiket