Custom
Middle English: from Old French coustume, based on Latin consuetudo, from consuetus, past participle of consuescere ‘accustom’, from con- (expressing intensive force) + suescere ‘become accustomed’.
wiktionary
From Middle English custume, borrowed from Anglo-Norman custume, from Old French coustume, from a Vulgar Latin*cōnsuētūmen or *costūmen, from Latin cōnsuētūdinem, accusative singular of cōnsuētūdō(“custom, habit”), from cōnsuēscō(“accustom, habituate”), from con-(“with”) + suēscō(“become used or accustomed to”). First element con- derives from cum, from Old Latin com, from Proto-Italic *kom, from Proto-Indo-European *ḱóm(“with, along”). Second element suēscō is from Proto-Indo-European *swe-dʰh₁-sk-, from *swé(“self”) + *dʰeh₁-(“to put, place, set”); related to Latin suus(“one's own, his own”). 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”)). Doublet of costume and consuetude.
Adjective form circa 1830.
etymonline
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]
custom (adj.)
"made to measure or order, done or made for individual customers," by 1830, from custom (n.).
