What does avow mean?
The definition of avow
A*vow”, v. t.
[imp. & p. p. Avowed (p. pr. & vb. n. Avowing.] Etym: [F. avouver, fr. L. advocare to call to (whence the meanings, to call upon as superior; recognize as lord, own, confess); ad + vocare to call. See Advocate, Avouch.]

1 To declare openly, as something believed to be right; to own or acknowledge frankly; as, a man avows his principles or his crimes. Which I to be the of Israel’s God Avow, and challenge Dagon to the test. Milton.
2 (Law)
To acknowledge and justify, as an act done. See Avowry. Blackstone.

Synonyms
— To acknowledge; own; confess. See Confess.

A*vow”, n,
Etym: [Cf. F. aveu.]

Avowal. [Obs.] Dryden.

A*vow”, v. t. & i.
Etym: [OF. avouer, fr. LL. votare to vow, fr. L. votun. See Vote, n.]

To bind, or to devote, by a vow. [Obs.] Wyclif.

A*vow”, n.
A vow or determination. [Archaic]