Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
From Middle English custume, from Anglo-Norman custume, from Old French coustume, from Vulgar Latin *cōnsuētūmen, from Latin cōnsuētūdinem, accusative singular of cōnsuētūdō (“custom, habit”), from cōnsuēscō (“accustom, habituate”), from con- (“with”) + suēscō (“become used or accustomed”), inchoative form of sueō (“I am accustomed”), perhaps from suus (“one's own, his own”); see consuetude. Displaced native Middle English wune, wone (“custom, habit, practice”) (from Old English wuna (“custom, habit, practice, rite”)), Middle English side, sid (“custom”) (from Old English sidu, sido (“custom, note, manner”)), Middle English cure (“custom, choice, preference”) (from Old English cyre (“choice, choosing, free will”)).
custom (plural customs)
- Frequent repetition of the same behavior; way of behavior common to many; ordinary manner; habitual practice; usage; method of doing, living or behaving.
- 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. - Joseph Addison.
- (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. Wharton.
- (obsolete) Familiar acquaintance; familiarity.
- Age can not wither her, nor custom stale Her infinite variety. Shakespeare
- 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.
- created under particular specifications, specialized, unique, custom-made
Derived terms 
custom (not comparable)
- made in a different way from usual, specially to fit one's needs
- My feet are as big as powerboats, so I need custom shoes.
- (obsolete) (transitive) To make familiar; to accustom.
- (obsolete) (transitive) To supply with customers.
- (obsolete) (transitive) To pay the customs of.
- (obsolete) (intransitive) To have a custom.
- On a bridge he custometh to fight. Edmund Spenser.