cis-, prefix (opp. TRANS- or ULTRA-).
1 on this side of; on the side nearer to the speaker or writer (cisatlantic).
2 Rom. Antiq. on the Roman side of (cisalpine).
3 (of time) closer to the present (cis-Elizabethan).
4 Chem. (of an isomer) having two atoms or groups on the same side of a given plane in the molecule.
L cis on this side of