C (from C to C)
C2 (from C2c to C2c)
C5 (from C5 to C5)
C_ (from C-12 Huron to Côtes-d'Armor)
Ca (from CA to Cazenovia, Wisconsin)
Cb (from CB to CBU-89 Gator)
Cc (from Cc to CCX)
Cd (from CD to CDU (disambiguation))
Ce (from CE to Cezzar Ahmet)
Cf (from CF18 to CFX)
Cg (from CG to CGS)
Ch (from CH-46 Sea Knight to Chytrid)
Ci (from CIA cryptonym to Cizin)
Cj (from CJ to CJTT)
Ck (from CKC to CKWS)
Cl (from CL to Clytia)
Cm (from CM to CMYK)
Cn (from CN (disambiguation) to Cnut)
Co (from CO2 sink to Cozy Powell)
Cp (from CP to CPUSA)
Cq (from CQ to CQD)
Cr (from Crab to Crystallomancy)
Cs (from CS to CSX Transportation)
Ct (from CT to CTY)
Cu (from Cu Chi tunnels to Cuzco)
Cv (from CV to CVS)
Cw (from CW complex to CWU)
Cx (from Cx to CX)
Cy (from Cy Young to Cyzicus)
Cz (from Czardas to Czochralski process)