trend (n.) Look up trend at Dictionary.com
"the way something bends" (coastline, mountain range, etc.), 1777, earlier "round bend of a stream" (1620s), from trend (v.); sense of "general course or direction" is from 1884. Sense of "a prevailing new tendency in popular fashion or culture" is from c. 1950.
trend (v.) Look up trend at Dictionary.com
1590s, "to run or bend in a certain direction" (of rivers, coasts, etc.), from Middle English trenden "to roll about, turn, revolve," from Old English trendan "turn round, revolve, roll," from Proto-Germanic *trandijan (source also of Old English trinde "round lump, ball," Old Frisian trind, Middle Low German trint "round," Middle Low German trent "ring, boundary," Dutch trent "circumference," Danish trind "round"); origin and connections outside Germanic uncertain. Sense of "have a general tendency" (used of events, opinions, etc.) is first recorded 1863, from the nautical sense. Related: Trended; trending.
trendsetter (n.) Look up trendsetter at Dictionary.com
also trend-setter, 1950, from trend (n.) + agent noun from set (v.). Related: Trend-setting.
trendy (adj.) Look up trendy at Dictionary.com
1962, from trend (n.) + -y (2). Related: Trendily; trendiness.
trundle (n.) Look up trundle at Dictionary.com
"small wheel to support heavy weights," 1540s (implied in trundle bed "low bed on small wheels"), possibly from Middle English trendle "wheel, suspended hoop" (early 14c.), from Old English trendel "ring, disk" (see trend (v.)). Also probably in part from Old French trondeler "to roll down, fall down," which is of Germanic origin.
uptick (n.) Look up uptick at Dictionary.com
"upward trend," 1962, an economist's term, from up (adv.) + tick (v.), in reference to some recording mechanism.
inexpressible (adj.) Look up inexpressible at Dictionary.com
1620s, from in- (1) "not" + expressible (see express (v.)). Inexpressibles "trousers" is from 1790. Related: Inexpressibly.
I have retain'd the word BREECHES, as they are known by no other name amongst country folk.--The change from vulgarity to refinement, in cities and towns, has introduced other appellations; there they are generally called SMALL CLOTHES, but some ladies of high rank and extreme delicacy call them INEXPRESSIBLES. [footnote in "Poems Miscellaneous and Humorous," by Edward Nairne, Canterbury, 1791]
Inexpressibles is the earliest recorded and thus seems to have begotten the trend: Unmentionables (1806); indispensibles (1820); ineffables (1823); unutterables (1826); innominables (1827); and inexplicables (1829) followed.