S: (n) eon, aeon (the longest division of geological time)
S: (n) period, geological period (a unit of geological time during which a system of rocks formed) "ganoid fishes swarmed during the earlier geological periods"
S: (n) era, geological era (a major division of geological time; an era is usually divided into two or more periods)
S: (n) epoch (a unit of geological time that is a subdivision of a period and is itself divided into ages)
W: (adj) eonian [Related to: eon] (continuing forever or indefinitely) "the ageless themes of love and revenge"; "eternal truths"; "life everlasting"; "hell's perpetual fires"; "the unending bliss of heaven"
S: (n) eon, aeon ((Gnosticism) a divine power or nature emanating from the Supreme Being and playing various roles in the operation of the universe)