"to have actual being of any kind, actually be at a certain moment or throughout a certain period of time," c. 1600, from French exister (17c.), from Latin existere/exsistere "to step out, stand forth, emerge, appear; exist, be" (see existence). "The late appearance of the word is remarkable" [OED]. Middle English often used ibēn, ibeon (based on be) for "to exist." Related: Existed; existing.
1860, a colloquial shortening of photograph. The verb is by 1865, from the noun. Photo-finish, of a race that ends with two or more competitors crossing the finishing line at nearly the same time (so a photograph taken at the finish line at the moment of crossing is the only way to determine who won) is attested from 1936. Photo opportunity "arranged opportunity to take a photograph of a notable person or event" is from 1974, said to be a coinage of the Nixon Administration.
"notch, groove, slit," mid-15c., nik, nyke, a word of unknown origin, possibly from a variant of Old French niche (see niche). Nick of time is first attested 1640s (nick of opportunity is 1610s), possibly from an old custom of recording time as it passed by making notches on a tally stick, though nick in the general sense of "critical moment" is older (1570s, Hanmer, who adds "as commonly we say") than the phrase. Nick (n.) specifically as "notch of a tally" is attested from late 15c.
"melody for a single voice," 1775, from Italian aria, literally "air" (see air (n.1)).
Historically considered, the aria marks a single moment in the course of a dramatic action. The text often consists of but a few words, many times repeated (as we find in Handel's oratorios, etc.), and the musical development is the main thing. The opposite of aria is recitative (q.v.), in which the declamation of the syllables is the main thing, colored, perhaps, by means of clever orchestration. [W.S.B. Mathews and Emil Liebling, "Dictionary of Music," 1896]
As a noun in astrology, "point of the ecliptic or sign of the zodiac which is on the eastern horizon at the moment of birth." The planet that rules the ascendant is believed to have predominant influence on the horoscope. Hence in the ascendant "ruling, dominant" (not, as is often thought, "rising"), 1670s, and the adjective meaning "superior, dominant," 1806.
also sentimentalise, 1764, intransitive, "indulge in sentiments, play the sentimentalist," from sentimental + -ize. Meaning "to make sentimental" (transitive) is from 1813. Related: Sentimentalized; sentimentalizing.
Think on these things, and let S______ go to Lincoln sessions by himself, and talk classically with country justices. In the meantime we will philosophize and sentimentalize;—the last word is a bright invention of the moment in which it was written, for yours or Dr. Johnson's service .... [Laurence Sterne, letter to William Combe, Esq., dated Aug. 5, 1764, published 1787]