C0 or C00 has several uses including: C0, the IATA code for Centralwings airline C0 and C1 control codes a CPU power state in the Advanced Configuration and Power Interface an alternate name for crt0, a library used in the startup of a C program in mathematics: the differentiability class C0 a C0-semigroup, a strongly continuous one-parameter semigroup c0, the Banach space of real sequences that converge to zero a C0 field is an algebraically closed field in physics, c0, the speed of light in vacuum in chemistry, C°, the standard state for solute concentration %C0, the URL-encoded version of the character "À" C0, a note-octave in music an ISO 216 paper format size C00, the ICD-10 code for oral cancer See also CO (disambiguation), the two letter combination