Online Etymology Dictionary

suitability (n.): 1680s, from suitable + -ity.
suitable (adj.): 1580s, from suit + -able. Earlier suit-like (1560s); suitly (mid-15c.).
suitably (adv.): 1570s, from suitable + -ly (2).
suitcase (n.): 1902, from suit (n.) + case (n.2). Originally a case for holding a suit of clothes.
suite (n.): 1670s, "train of followers or attendants," from French suite, from Old French suite "act of following, attendance" (see suit). The meanings "set of instrumental compositions" (1680s), "connected set of rooms" (1716), and "set of furniture" (1805) were borrowed from French or re-spelled from suit on the French model.
suitor (n.): late 14c., "follower, disciple," from Anglo-French seutor or directly from Late Latin secutor, from past participle stem of sequi "to follow" (see suit (n.)). Meaning "one who seeks (a woman) in marriage" is from 1580s.
Sulawesi: see Celebes.
sulcus (n.): plural sulci, Latin, literally "furrow, trench, ditch, wrinkle."
sulfa: 1942, short name for the group of drugs derived from sulfanilamide ("amide of sulfanilic acid," which is so called because it is a sulphonic derivative of the dye-stuff aniline), and shortened from that word. (The usual British English spelling is sulpha.)
sulfate (n.): 1790 (sulphat), from French sulphate (1787), from Modern Latin sulphatum acidum, from Latin sulpur, sulphur (see sulfur) + chemical ending -ate (3). The spelling with -ph- is standard in Britain.
sulfur (n.): also sulphur, c.1300, from Old French soufre (13c.), from Late Latin sulfur, from Latin sulphur, probably from a root meaning "to burn." Ousted native brimstone and cognate Old English swefl.
sulfuric (adj.): also sulphuric, 1790, from French sulfurique; see sulfur + -ic.
sulfurous (adj.): also sulphurous, 1530s, from Latin sulphurosus or a native formation from sulfur + -ous. Related: Sulfurously; sulphurously.
sulfurous (adj.): also sulfurous, 1520s, "of the nature of brimstone," from sulfur + -ous. Hence figurative use with suggestions of hellfire (c.1600). Scientific chemistry sense is from 1790. Earlier in the "brimstone-like" sense was sulphurious (late 15c.).
sulk (v.): 1781, back-formation of sulky (adj.). Related: Sulked; sulking.
sulky (adj.): "sullen," 1744, probably from Old English asolcen "idle, lazy, slow," from past participle of aseolcan "become sluggish, be weak or idle" (related to besylcan "be languid"), from Proto-Germanic *seklanan (cf. Middle High German selken "to drop, fall").
sulky (n.): "light carriage with two wheels," 1756, apparently a noun use of sulky (adj.), on notion of "standoffishness," because the carriage has room for only one person.
sullen (adj.): 1570s, alteration of Middle English soleyn "unique, singular," from Anglo-French *solein, formed on the pattern of Old French soltain, from Old French soul "single" (see sole (n.2)). The sense shift in Middle English from "solitary" to "morose" occurred late 14c.
sully (v.): 1570s (implied in sulliedness), probably from Middle French souiller, from Old French souillier "make dirty" (see soil (v.)). Related: Sullied; sullying.
sulphur (n.): see sulfur. The form prefered in Britain; the spelling's suggestion of a Greek origin is misleading.
sulphuric (adj.): see sulfuric.
sulphurous (adj.): see sulfurous.
sultan (n.): 1550s, from Middle French sultan "ruler of Turkey" (16c.), from Arabic sultan "ruler, king, queen, power, dominion," from Aramaic shultana "power," from shelet "have power." His wife, mother, daughter, concubine, or sister is a sultana.
sultana (n.): 1580s, from Italian sultana, fem. of sultano (see sultan).
sultanate (n.): 1822, from sultan + -ate.
sultry (adj.): 1590s, "oppressively hot, close and moist" (of weather), from obsolete verb sulter "to swelter" (1580s), alteration of swelter. Figurative sense of "hot with lust" is attested from 1704; of women, "lascivious, sensual, arousing desire" it is recorded from 1940.
sum (n.): late 13c., "quantity or amount of money," from Anglo-French and Old French summe (13c.), from Latin summa "total number, whole, essence, gist," noun use of fem. of summus "highest," from PIE *sup-mos-, from root *uper "over" (see super-).

The sense development from "highest" to "total number" is probably via the Roman custom of adding up a stack of figures from the bottom and writing the sum at the top, rather than at the bottom as we do now (cf. the bottom line). Meaning "total number of anything" is recorded from late 14c. Meaning "essence of a writing or speech" also is attested from late 14c. The verb is attested from c.1300; meaning "briefly state the substance of" (now usually with up) is first recorded 1620s. Sum-total is attested from late 14c., from Medieval Latin summa totalis.
sumac (n.): c.1300, "preparation of dried, chopped leaves of a plant of the genus Rhus" (used in tanning and dyeing and as an astringent), from Old French sumac (13c.), from Medieval Latin sumach, from Arabic summaq, from Syrian summaq "red." Later applied to a North American plant species.
Sumerian (adj.): 1874, from French Sumérien (1872), from Sumer, name of a district in ancient Babylonia.
summa cum laude: 1900, Latin, literally "with highest praise."
summarily (adv.): 1520s, from summary + -ly (2).
summarise (v.): chiefly British English spelling of summarize; for suffix, see -ize. Related: Summarised; summarising.
summarization (n.): 1860, noun of action from summarize.
summarize (v.): 1837, American English, from summary + -ize. Related: Summarized; summarizing.
summary (adj.): early 15c., from Medieval Latin summarius "of or pertaining to the sum or substance," from Latin summa "whole, gist" (see sum). Sense of "done promptly" is first found 1713. The noun meaning "a summary statement or account" is first recorded c.1500, from Latin summarium "an epitome, abstract, summary," from summa "totality, gist."
summate (v.): 1900, Modern Latin summatus, past participle of summare "to sum" (see summation). Related: Summated; summating.
summation (n.): 1760, from Modern Latin summationem (nominative summatio) "an adding up," from Late Latin summatus, past participle of summare "to sum up," from Latin summa (see sum).
summative (adj.): 1836, from Modern Latin summat-, stem of summatus (see summation) + -ive.
summer (n.1): "hot season of the year," Old English sumor, from Proto-Germanic *sumur- (cf. Old Saxon, Old Norse, Old High German sumar, Old Frisian sumur, Middle Dutch somer, Dutch zomer, German Sommer), from PIE root *sem- (cf. Sanskrit sama "season, half-year," Avestan hama "in summer," Armenian amarn "summer," Old Irish sam, Old Welsh ham, Welsh haf "summer"). Old Norse sumarsdag, first day of summer, was the Thursday that fell between April 9 and 15.

Summer camp is attested from 1893; summer resort is from 1832; summer school first recorded 1860; theatrical summer stock is attested from 1942.
summer (n.2): "horizontal bearing beam," late 13c., from Anglo-French sumer, Old French somer "main beam," originally "pack horse," from Vulgar Latin *saumarius, from Late Latin sagmarius "pack horse," from sagma "packsaddle" (see sumpter).
summer (v.): "to pass the summer," mid-15c., from summer (n.1). Related: Summered; summering.
summerize (v.): 1797, "to spend the summer," from summer (n.1) + -ize. From 1935 as "to prepare for summer." Related: Summerized; summerizing.
summertime (n.): late 14c., somer tyme, from summer (n.1) + time (n.). Earlier were summertide (mid-13c.), sumeres tid (late Old English). In Britain, as two words, with reference to what in U.S. is daylight saving time, recorded from 1916.
summery (adj.): 1824, from summer (n.1) + -y (2).
summit (n.): late 15c., from Middle French somete, from Old French sommette, diminutive of som, sum "highest part, top of a hill," from Latin summum, noun use of neuter of summus "highest," related to super "over" (see super-). The meaning "meeting of heads of state" (1950) is from Winston Churchill's metaphor of "a parley at the summit."
summon (v.): c.1200, from Anglo-French, Old French sumundre "summon," from Vulgar Latin *summundre "to call, cite," from Latin summonere "hint to," from sub "under" + monere "warn, advise" (see monitor (n.)). Summons "authoritative call to be at a certain place for a certain purpose" is late 13c., from Old French sumunse, noun use of fem. past participle of somondre. Summoner "petty officer who cites persons to appear in court" is from early 14c.; contracted form sumner is from mid-14c.
summum bonam: Latin, literally "highest good" (in ethics), from Cicero.
sumo (n.): 1880, from Japanese sumo "to compete."
sump (n.): early 15c., "marsh, morass," from Middle Dutch somp or Middle Low German sump, from Proto-Germanic *sumpaz. Meaning "pit to collect water" is first found 1650s.
sumpter (n.): early 14c., "driver of a pack horse," from Old French sommetier, from Vulgar Latin *sagmatarius "a pack horse driver," from Late Latin sagmat- "a pack, burden," stem of sagma "packsaddle," from Greek sagma, probably related to sattein "to pack, press, stuff." Used from mid-15c. of horses and mules for carrying loads.