late 14c., originally an adverb, "moreover, in addition," from Latin item (adv.) "likewise, just so, moreover," probably from ita "thus," id "it" (see id) + adverbial ending -tem (compare idem "the same").

The Latin adverb was used to introduce a new fact or statement, and in French and English it was used before every article in an enumeration (such as an inventory or bill). This practice led to the noun sense "an article of any kind" (1570s). Meaning "detail of information" (especially in a newspaper) is from 1819; item "sexually linked unmarried couple" is 1970, probably from notion of being an item in the gossip columns.

"state by items, give the particulars of," 1833 (implied in itemized), American English, from item + -ize. Related: Itemizing. An earlier verb was item "make a note of" (c. 1600).

"an item on an agenda;" see agenda.

"gadget, small manufactured item," c. 1920, American English, probably an alteration of gadget, perhaps based on which it.

"small item of ornamental jewelry," 1660s, from French bijou, which according to OED is probably from Breton bizou "(jeweled) ring," from bez "finger" (compare Cornish bisou "finger-ring," 13c.). Related: Bijouterie.

c. 1500, "in a serious manner, with serious thought or application," from serious (adj.) + -ly (2). By 1765 as "to a serious extent, so as to give grounds for alarm." To take (something) seriously "be earnest in one's attitude toward" is from 1782.

Middle English also had seriousli "minutely, in detail" (late 14c., now obsolete), from Medieval Latin seriose "item by item, in detail," which reflects the confusion with the stem of series, for which confusion see serious (adj.). Caxton (mid-15c.) uses seriately for "attentively, earnestly."

"all things, taken separately; any total or aggregate considered with reference to its constituent parts; each separate item or particular," late 14c., from every + thing. Colloquially, "something of extreme importance," by 1889.

also what-not, 1530s, "anything," from what + not. Elliptical for "what may I not say," implying "everything else." As the name of a furniture item, first attested 1808, so named for the objects it is meant to hold.

also deaccession, "remove an entry for an item from the register of a museum, library, etc." (often a euphemism for "to sell"), by 1968, from de- "off, away" + accession, which had been used since 1887 in library publications as a verb meaning "to add to a catalogue." Related: De-accessioned; de-accessioning.

type of popular music blending elements of rock 'n' roll and hillbilly music, 1956, from rock (n.2) in the music sense + second element abstracted from hillbilly music. One of the first uses is in a Billboard magazine item about Johnny Burnette's "Lonesome Train."