chronos (Greek #5550)
a space of time (in general, and thus properly distinguished from 2540, which designates a fixed or special occasion; and from 165, which denotes a particular period) or interval; by extension, an individual opportunity; by implication, delay
KJV usage: + years old, season, space, (X often-)time(-s), (a) while.
Pronounce: khron'-os
Origin: of uncertain derivation
aionios (Greek #166)
perpetual (also used of past time, or past and future as well)
KJV usage: eternal, for ever, everlasting, world (began).
Pronounce: ahee-o'-nee-os