What does accustom mean?
The definition of accustom
Ac*cus”tom, v. t.
[imp. & p. p. Accustomed; p. pr. & vb. n.Accustoming.]
Etym: [OF. acostumer, acustumer, F. accoutumer; à (L. ad) + OF. costume, F. coutume, custom. See Custom.]

To make familiar by use; to habituate, familiarize, or inure; – – with to. I shall always fear that he who accustoms himself to fraud in little things, wants only opportunity to practice it in greater. Adventurer.

Synonyms
— To habituate; inure; exercise; train.

Ac*cus”tom, v. i.
1 To be wont. [Obs.] Carew.
2 To cohabit. [Obs.] We with the best men accustom openly; you with the basest commit private adulteries. Milton.
Ac*cus”tom, n.
Custom. [Obs.] Milton.