Etymology
Advertisement
custom (adj.)

"made to measure or order, done or made for individual customers," by 1830, from custom (n.).

Related entries & more 
Advertisement
custom (n.)

c. 1200, custume, "habitual practice," either of an individual or a nation or community, from Old French costume "custom, habit, practice; clothes, dress" (12c., Modern French coutume), from Vulgar Latin *consuetumen, from Latin consuetudinem (nominative consuetudo) "habit, usage, way, practice, tradition, familiarity," from consuetus, past participle of consuescere "accustom," from com-, intensive prefix (see com-), + suescere "become used to, accustom oneself," related to sui, genitive of suus "oneself," from PIE *swe- "oneself" (see idiom).

Custom implies continued volition, the choice to keep doing what one has done; as compared with manner and fashion, it implies a good deal of permanence. [Century Dictionary]

A doublet of costume. An Old English word for it was þeaw. Meaning "the practice of buying goods at some particular place" is from 1590s. Sense of a "regular" toll or tax on goods is early 14c. The native word here is toll (n.).

Custom-house "government office at a point of import and export for the collection of customs" is from late 15c. Customs "area at a seaport, airport, etc., where baggage is examined" is by 1921.

Old customs! Oh! I love the sound,
  However simple they may be:
Whate'er with time has sanction found,
  Is welcome, and is dear to me.
Pride grows above simplicity,
  And spurns it from her haughty mind,
And soon the poet's song will be
  The only refuge they can find.
[from "December," John Clare, 1827]
Related entries & more 
customize (v.)

"to make (something) to a customer's specifications," 1934, American English, from custom (adj.) + -ize. Related: Customizable; customized; customizing.

Related entries & more 
accustom (v.)

"familiarize by custom or use," early 15c., accustomen, from Old French acostumer "become accustomed; accustom, bring into use" (12c., Modern French accoutumer), from à "to" (see ad-) + verb from costume "habit, practice" (see custom (n.)). Related: Accustomed; accustoming.

Related entries & more 
customary (adj.)

1520s, "liable to customs or dues;" c. 1600, "according to established usage, habitual," from Medieval Latin custumarius, from Latin consuetudinarius, from consuetitudinem (see custom (n.)). In Middle English it was a noun, "written collection of customs" of a manor or community. Earlier words for "according to established usage" were custumal (c. 1400, from Old French), custumable (c. 1300). Related: Customarily.

Related entries & more 
Advertisement
customer (n.)

late 14c., custumer, "customs official, toll-gatherer;" c. 1400, "one who purchases goods or supplies, one who customarily buys from the same tradesman or guild," from Anglo-French custumer, Old French coustumier, from Medieval Latin custumarius "a toll-gatherer, tax-collector," literally "pertaining to a custom or customs," a contraction of Latin consuetudinarius, from consuetudo "habit, usage, practice, tradition" (see custom (n.)).

The more generalized meaning "a person with whom one has dealings" emerged 1540s; that of "a person to deal with" (usually with a defining adjective: tough, etc.) is by 1580s. In Shakespeare, the word also can mean "prostitute."

Related entries & more 
costume (n.)

1715, "style of dress," but also more broadly "custom or usage with respect to place and time, as represented in art or literature; distinctive action, appearance, arms, furniture, etc.," from French costume (17c.), from Italian costume "fashion, habit," from Latin consuetudinem (nominative consuetudo) "custom, habit, usage." Essentially the same word as custom but arriving by a different path.

It originally was an art term, referring to congruity in representation. From "customary clothes of the particular period in which the scene is laid," the meaning broadened by 1818 to "any defined mode of dress, external dress." Costume jewelry, made to be worn as an accessory to fashionable costume, is attested by 1917. Related: Costumic.

Related entries & more 
usage (n.)
c. 1300, "established practice, custom," from Anglo-French and Old French usage "custom, habit, experience; taxes levied," from us, from Latin usus "use, custom" (see use (v.)). From late 14c. as "service, use, act of using something."
Related entries & more 
wont (n.)
"habitual usage, custom," c. 1400, from wont, adjective and verb.
Related entries & more 
Boxing Day (n.)
1809, "first weekday after Christmas," on which by an English custom postmen, employees, and others can expect to receive a Christmas present; originally in reference to the custom of distributing the contents of the Christmas box, which was placed in the church for charity collections. See box (n.1). The custom is older than the phrase.
Related entries & more