Online Etymology Dictionary

occurrence: 1530s, from M.L. occurrentia, from L. occurrere (see occur).
occur: 1520s, "meet, meet in argument," from M.Fr. occurrer, from L. occurrere "run to meet, run against, befall, present itself," from ob "against, toward" + currere "to run" (see current). Sense development is from "meet" to "present itself" to "appear" to "happen" ("present itself in the course of events"). Meaning "to come into one's mind" is from 1620s. Related: Occurred.
happen: c.1300, happenen "to come to pass, occur," originally "occur by hap" (see hap); replaced O.E. gelimpan, gesceon, and M.E. befall. Related: Happened.
post-millennial: 1851, from post- "after" + millennial; chiefly in ref. to the Protestant doctrine that the second coming of Christ will occur after, not at, the Christian millennium.
synchronize: c.1624, "to occur at the same time," from Gk. synchronizein "be of the same time," from synchronos "happening at the same time" (see synchronous). The sense of "make synchronous" is first recorded 1806. Synchronized swimming is recorded from 1950.
unlike: c.1200, "Not resembling," from un- (1) "not" + like. Cf. O.E. ungelic, O.Fris. unlik, O.N. ulikr, M.Da. ulige. Unlikely "not likely to occur" is attested from late 14c. (cf. O.N. ulikligr, M.Da. uligelig). Meaning "not likely to be true" is recorded from 1590s.
aught (1): "something," O.E. awiht "aught, anything, something," lit. "e'er a whit," from P.Gmc. *aiwi "ever" (from PIE *aiw- "vital force, life, long life, eternity") + *wihti "thing, anything whatever" (see wight). In Shakespeare, Milton and Pope, aught and ought occur indiscriminately.
second (adj.): "after first," c.1300, from O.Fr. second, from L. secundus "following, next in order," from root of sequi "follow" (see sequel). Replaced native other (q.v.) in this sense because of the ambiguousness of the earlier word. Second-rate is from 1669, originally of ships (see rate); second sight is from 1616; an etymologically perverse term, since it means in reality the sight of events before, not after, they occur. Second fiddle first attested 1809.
nines: in phrase to the nines "to perfection" (1787) first attested in Burns, apparently preserves the ancient notion of the perfection of the number as three times three (e.g. the nine Muses, etc.
[T]he Book of St. Albans, in the sections on blasonry, lays great stress on the nines in which all perfect things (orders of angels, virtues, articles of chivalry, differences of coat armour, etc.) occur. [Weekley]
No one seems to consider that it might be a corruption of to then anes, lit. "for the one (purpose or occasion)," a similar construction to the one that yielded nonce (q.v.).
blue moon: 1821 as a specific term in the sense "very rarely," perhaps suggesting something that, in fact, never happens (cf. at the Greek calends); suggested earliest in this couplet from 1528:
Yf they say the mone is blewe,
We must beleve that it is true.
Though this might refer to calendrical calculations by the Church, so that the general sense of the term and the specific one (commonly misinterpreted as "second full moon in a calendar month," but actually a quarterly calculation) are difficult to disentangle. In either case, the sense of blue is obscure. Literal blue moons do occasionally occur under extreme atmospheric conditions.
angry: mid-14c., from anger + -y. Originally "full of trouble, vexatious;" sense of "enraged, irate" is from late 14c. The phrase angry young man dates to 1941 but was popularized in ref. to the play "Look Back in Anger" (produced 1956) though it does not occur in that work. "There are three words in the English language that end in -gry. Two of them are angry and hungry. What is the third?" There is no third (except some extremely obscure ones). Richard Lederer calls this "one of the most outrageous and time-wasting linguistic hoaxes in our nation's history" and traces it to a New York TV quiz show from early 1975.
dog days: 1530s, from L. dies caniculares, from Greek; so called because they occur around the time of the heliacal rising of Sirius, the Dog Star (kyon seirios). Noted as the hottest and most unwholesome time of the year; usually July 3 to Aug. 11, but variously calculated, depending on latitude and on whether the greater Dog-star (Sirius) or the lesser one (Procyon) is reckoned. The heliacal rising of Sirius has shifted down the calendar with the precession of the equinoxes; in ancient Egypt c.3000 B.C.E. it coincided with the summer solstice, which also was the new year and the beginning of the inundation of the Nile. The "dog" association apparently began here (the star's hieroglyph was a dog), but the reasons for it are obscure.
save (v.): early 13c., "to deliver (one's soul) from sin and its consequences;" mid-13c., "to deliver or rescue from peril," from O.Fr. sauver, from L.L. salvare "make safe, secure," from L. salvus "safe" (see safe (adj.)). Meaning "store up, to keep instead of spending" is attested from mid-14c. Save face (1898) first was used among the British community in China and is said to be from Chinese; it has not been found in Chinese, but tiu lien "to lose face" does occur. To not (do something) to save one's life is recorded from 1848.
seraph: 1667, first used by Milton (probably on analogy of cherub/cherubim), singular back-formation from O.E. seraphim (pl.), from L.L. seraphim, from Gk. seraphim, from Heb. seraphim (only in Isa. vi), pl. of *saraph (which does not occur in the Bible), probably lit. "the burning one," from saraph "it burned." Seraphs were traditionally regarded as burning or flaming angels, though the word seems to have some etymological sense of "flying," perhaps from confusion with the root of Arabic sharafa "be lofty." Some scholars identify it with a word found in other passages interpreted as "fiery flying serpent."
come: O.E. cuman "come, approach, land; come to oneself, recover; arrive; assemble" (class IV strong verb; past tense cuom, com, pp. cumen), from P.Gmc. *kwem- (cf. O.S. cuman, O.Fris. kuma, M.Du. comen, Du. komen, O.H.G. queman, Ger. kommen, O.N. koma, Goth. qiman), from PIE base *gwem- "to go, come" (cf. Skt. gamati "he goes," Avestan jamaiti "goes," Tocharian kakmu "come," Lith. gemu "to be born," Gk. bainein "to go, walk, step," L. venire "to come"). Substitution of -o- for -u- is scribal change before minims (cf. monk, some, worm, originally munuc, sum, wyrm). Modern past tense form came is M.E., probably from O.N. kvam, replacing O.E. cuom. Remarkably productive with prepositions (NTC's "Dictionary of Phrasal Verbs" lists 198 combinations); consider the varied senses in come to "regain consciousness," come over "possess" (as an emotion), come at "attack," come on (interj.) "be serious," and come off "occur." For sexual senses, see cum.