Webster's Revised Unabridged Dictionary · 1913

Custom

Custom (kus"tum) , noun

[Old French custume, costume, Anglo-Norman coustome, French coutume, from (assumed) Late Latin consuetumen custom, habit, from Latin consuetudo, -dinis, from consuescere to accustom, verb inchoative from consuere to be accustomed; con- + suere to be accustomed, prob. originally, to make one's own, from the root of suus one's own; akin to English so, adv. Compare Consuetude, Costume.]

1.
Frequent repetition of the same act; way of acting common to many; ordinary manner; habitual practice; usage; method of doing or living.
And teach customs which are not lawful. — Acts xvi. 21
Moved beyond his custom, Gama said. — Tennyson
A custom More honored in the breach than the observance. — Shakespeare
2.
Habitual buying of goods; practice of frequenting, as a shop, manufactory, etc., for making purchases or giving orders; business support.
Let him have your custom, but not your votes. — Addison
3.
(Law) Long-established practice, considered as unwritten law, and resting for authority on long consent; usage. See Usage, and Prescription.

Usage is a fact. Custom is a law. There can be no custom without usage, though there may be usage without custom.

4.
Familiar acquaintance; familiarity. [Obsolete]
Age can not wither her, nor custom stale Her infinite variety. — Shakespeare
Collocations (3)
Custom of merchants , a system or code of customs by which affairs of commerce are regulated.
General customs , those which extend over a state or kingdom.
Particular customs , those which are limited to a city or district; as, the customs of London.

Custom , transitive verb

[Compare Old French costumer. Compare Accustom.]

1.
To make familiar; to accustom. [Obsolete] — Gray
2.
To supply with customers. [Obsolete] — Bacon

Custom , intransitive verb

To have a custom. [Obsolete]
On a bridge he custometh to fight. — Spenser

Custom , noun

[Old French coustume, French coutume, tax, i. e., the usual tax. See 1st Custom.]

1.
The customary toll, tax, or tribute.
Render, therefore, to all their dues: tribute to whom tribute is due; custom to whom custom. — Rom. xiii. 7
2.
Duties or tolls imposed by law on commodities, imported or exported.

Custom , transitive verb

To pay the customs of. [Obsolete] — Marlowe