What does allow mean?
The definition of allow
Al*low”, v. t.
[imp. & p. p. Allowed; p. pr. & vb. n. Allowing.]
Etym: [OE. alouen, OF. alouer, aloer, aluer, F. allouer, fr. LL. allocare to admit as proved, to place, use; confused with OF. aloer, fr. L. allaudare to extol; ad + laudare to praise. See Local, and cf. Allocate, Laud.]

1 To praise; to approve of; hence, to sanction. [Obs. or Archaic] Ye allow the deeds of your fathers. Luke xi. 48. We commend his pains, condemn his pride, allow his life, approve his learning. Fuller.
2 To like; to be suited or pleased with. [Obs.] How allow you the model of these clothes Massinger.
3 To sanction; to invest; to intrust. [Obs.] Thou shalt be . . . allowed with absolute power. Shak.
4 To grant, give, admit, accord, afford, or yield; to let one have; as, to allow a servant his liberty; to allow a free passage; to allow one day for rest. He was allowed about three hundred pounds a year. Macaulay.
5 To own or acknowledge; to accept as true; to concede; to accede to an opinion; as, to allow a right; to allow a claim; to allow the truth of a proposition. I allow, with Mrs. Grundy and most moralists, that Miss Newcome’s conduct . . . was highly reprehensible. Thackeray.
6 To grant (something) as a deduction or an addition; esp. to abate or deduct; as, to allow a sum for leakage.
7 To grant license to; to permit; to consent to; as, to allow a son to be absent.

Synonyms
— To allot; assign; bestow; concede; admit; permit; suffer; tolerate. See Permit.

Al*low”, v. i.
To admit; to concede; to make allowance or abatement. Allowing still for the different ways of making it. Addison. To allow of, to permit; to admit. Shak.