n. (also c) (pl. Cs or C's)
1 the third letter of the alphabet.
2 Mus. the first note of the diatonic scale of C major (the major scale having no sharps or flats).
3 the third hypothetical person or example.
4 the third highest class or category (of academic marks etc.).
5 Algebra (usu. c) the third known quantity.
6 (as a Roman numeral) 100.
7 (c) the speed of light in a vacuum.
symb. Chem. the element carbon.
abbr. (also C.)
3 Command Paper (second series, 1870-99).
4 Celsius, Centigrade.
5 coulomb(s), capacitance.
Useful english dictionary. 2012.