Lexical Definition

‎κεφάλαιον‎ kephálaion (kef-al'-ah-yon) sum ^G:N-N
neuter of a derivative of ‎κεφαλή‎

sum.

• a principal thing, i.e. main point
• specially, an amount (of money)

Abbott-Smith

κεφάλαιος, -α, -ον (< κεφαλή), [in LXX (-αιον, τό) for רֹאשׁ, Nu 4:2, al.;]
of the head; metaph., principal, chief; mostly as subst., κεφάλαιον, τό;
1. the chief point: He 8:1.
2. the sum total, amount: Ac 22:28 (other meaning, LS, s.v.).†

Abbott-Smith References

Liddell-Scott-Jones

κεφάλαιος-ος [ᾰ], α, ον,

(κεφαλή) of the head: metaphorically, principal, chief, ῥῆμα κ. (with a play on κεφαλίτης λίθος) [Refs 5th c.BC+]: superlative -ότατος variant in [Refs 5th c.BC+]

__II mostly substantive κεφάλαιοςον, τό, ={κεφαλή}, head, parts about the head, especially of fish, θύννου κ. τοδί Callias Comedy texts [Refs 5th c.BC+]; of an infant, [Refs 1st c.AD+]
__II.2 chief or main point, κ. δὴ παιδείας λέγομεν τὴν ὀρθὴν τροφήν [Refs 5th c.BC+]; especially in speaking or writing, sum, gist of the matter, κεφάλαιοςα λόγων [Refs 5th c.BC+]; τὰ κ. συγγράφων Εὐριπίδῃ drawing up the heads of the play, [Refs 5th c.BC+]; ἐν κεφαλαίῳ, or ὡς ἐν κ., εἰπεῖν to speak summarily, [Refs 5th c.BC+]; ἐν κεφαλαίοις ὑπομνῆσαι, ἀποδείξειν, περιλαβεῖν τι, [Refs 5th c.BC+]; τύπῳ καὶ ἐπὶ κεφαλαίου (variant -αίῳ), opposed to ἀκριβέστερον, [Refs 4th c.BC+]; especially in an argument, summing up, ἐν κεφαλαίοις [Refs 5th c.BC+]; κεφαλαίῳ δέ.., Latin denique, Decrees cited in [Refs 4th c.BC+]; συναγαγεῖν τὸ κ. to sum up, [Refs 4th c.BC+]
__II.3 metaphorically, of persons, the head or chief, ὅ τι περ κ. τῶν κάτωθεν, of Pericles, [Refs 5th c.BC+]; τὰ κ. τῶν μαθημάτων, of philosophers, [Refs 2nd c.AD+]; οἳ τὸ τῆς στάσεως κ. ἦσαν[Refs 2nd c.AD+]
__II.4 Rhet., head, topic of argument, [Refs 1st c.BC+]
__II.5 of money, capital, opposed to interest or income, [Refs 5th c.BC+]
__II.5.b sum total, [Refs 5th c.BC+]; πολλοῦ κ. for a large sum, [NT+1st c.AD+]; also σιτικὰ καὶ ἀργυρικὰ κ. [Refs 2nd c.AD+]
__II.6 crown, completion of a thing, τὸ μὲν κ. τῶν ἀδικημάτων the crowning act of wrong, [Refs 4th c.BC+]
__II.7 chapter, section, PGnom.Prooem., [Refs 5th c.AD+]; distinguished from τίτλος, [Refs]

_{LSJ Scripture Refs: Acts.22.28}