Janus-headed a. : Double-headed.

Example:


Taxonomy
Janus, god, the doors, temple of Janus, gates, Janus Geminus, Articles with unsourced statements, Janus Bifrons, Ianus, deities, myths, free encyclopedia, Origins, temple, Arch of Janus, Search, Macrobius, worshipped.

Defination from the web:
Janus (or Ianus) was the god of gates, doors, doorways, beginnings and endings. ... In Rome, Janus was worshipped in the Ianus geminus, a walled enclosure with gates at each end, situated in the Roman Forum which had been consecrated by Numa Pompilius. ...