Strong's G2310 — θεμέλιος (noun)
themelios (them-el'-ee-os) n.
1. something put down, i.e. a substructure (of a building, etc.)
{literally or figuratively}
[from a derivative of G5087]
KJV: foundation 
Root(s): G5087 
Hebrew root: τίθημι
Occurrences: 16