κεφάλαιος, -α, -ον (κεφαλή), [in LXX (-αιον, τό) for רֹאשׁ, Num_4:2, al. ;] of the head; metaphorically, principal, chief; mostly as subst., κεφάλαιον, τό; 1. the chief point: Heb.8:1. 2. the sum total, amount: Act.22:28 (other meaning, LS, see word).† (AS)
STRONG'S WORD STUDY
G2774 — κεφάλαιος
kephalaios · sum · Greek