Strong's G166 — αἰώνιος (adjective)
aionios (ai-o'-nee-os) adj.
1. perpetual (also used of past time, or past and future as well)
[from G165]
KJV: eternal, for ever, everlasting, world (began) 
Root(s): G165 
Hebrew root: αἰών
Occurrences: 71