Etymology
Advertisement
ordinary (adj.)

c. 1400, ordinarie, "regular, customary, belonging to the usual order or course, conformed to a regulated sequence or arrangement," from Old French ordinarie "ordinary, usual" and directly from Latin ordinarius "customary, regular, usual, orderly," from ordo (genitive ordinis) "row, rank, series, arrangement" (see order (n.)).

From 1580s as "common in occurrence, not distinguished in any way." Its various noun uses, dating to late 14c. and common until 19c., are now largely extinct except in out of the ordinary (1893) in which the sense of ordinary is "established or due sequence; something regular or customary." In British education, Ordinary level (abbrev. O level), "lowest of the three levels of General Certificate of Education," is attested from 1947. Related: Ordinarily.

Related entries & more 
Advertisement
ornery (adj.)

1816, ornary, American English dialectal contraction of ordinary (adj.). "Commonplace," hence "of poor quality, coarse, ugly." By c. 1860 the sense had evolved to "mean, cantankerous." Related: Orneriness.

Related entries & more 
*ar- 
also arə-, Proto-Indo-European root meaning "to fit together."

It forms all or part of: adorn; alarm; aristarchy; aristo-; aristocracy; arm (n.1) "upper limb of the body;" arm (n.2) "weapon;" armada; armadillo; armament; armature; armilla; armistice; armoire; armor; armory; army; art (n.) "skill as a result of learning or practice;" arthralgia; arthritis; arthro-; arthropod; arthroscopy; article; articulate; artifact; artifice; artisan; artist; coordination; disarm; gendarme; harmony; inert; inertia; inordinate; ordain; order; ordinal; ordinance; ordinary; ordinate; ordnance; ornament; ornate; primordial; subordinate; suborn.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit irmah "arm," rtih "manner, mode;" Armenian arnam "make," armukn "elbow;" Greek arti "just," artios "complete, suitable," artizein "to prepare," arthron "a joint;" Latin ars (stem art-) "art, skill, craft," armus "shoulder," artus "joint," arma "weapons;" Old Prussian irmo "arm;" German art "manner, mode."
Related entries & more 
run-of-the-mill (adj.)

"ordinary, unspectacular," 1922, a figurative use of a commercial phrase attested by 1909 in reference to material yielded by a mill (n.1), etc., before sorting for quality (compare common run "usual, ordinary type," from 1712). From run (n.) on the notion of "a continuous stretch of grinding."

Related entries & more 
policeman (n.)

"one of the ordinary police, a police patrolman," 1790, from police (n.) + man (n.).

Related entries & more 
Advertisement
undress (n.)
"state of partial or incomplete dress," 1680s, from undress (v.). Meaning "ordinary dress" is from 1748.
Related entries & more 
low (n.1)
"the ordinary sound uttered by an ox or cow" [OED], 1540s, from low (v.); ultimately imitative.
Related entries & more 
koinonia (n.)
"Christian fellowship," 1865, Greek, literally "communion, fellowship," from koinos "common, ordinary" (see coeno-).
Related entries & more 
plain clothes (n.)

"ordinary dress of civil life" (as opposed to military uniform), 1822; in reference to police detectives, it is attested from 1842. Also plainclothes.

Related entries & more 
oddness (n.)

late 14c., oddenesse, "unevenness of number," from odd + -ness. Meaning "strangeness, queerness, divergence from what is ordinary or useful" is from 1610s.

Related entries & more