mid-15c., "sweetheart chosen on St. Valentine's Day," from Late Latin Valentinus, the name of two early Italian saints (from Latin valentia "strength, capacity;" see valence). Choosing a sweetheart on this day originated 14c. as a custom in English and French court circles. Meaning "letter or card sent to a sweetheart" first recorded 1824. The romantic association of the day is said to be from it being around the time when birds choose their mates.
For this was on seynt Volantynys day
Whan euery bryd cometh there to chese his make.
[Chaucer, "Parlement of Foules," c. 1381]
Probably the date was the informal first day of spring in whatever French region invented the custom (many surviving medieval calendars reckon the start of spring on the 7th or 22nd of February). No evidence connects it with the Roman Lupercalia (an 18c. theory) or to any romantic or avian quality in either of the saints. The custom of sending special cards or letters on this date flourished in England c. 1840-1870, declined around the turn of the 20th century, and revived 1920s.
To speak of the particular Customs of the English Britons, I shall begin with Valentine's Day, Feb. 14. when young Men and Maidens get their several Names writ down upon Scrolls of Paper rolled up, and lay 'em asunder, the Men drawing the Maidens Names, and these the Mens; upon which, the Men salute their chosen Valentines and present them with Gloves, &c. This Custom (which sometimes introduces a Match) is grounded upon the Instinct of Animals, which about this Time of the Year, feeling a new Heat by the approach of the Sun, begin to couple. ["The Present State of Great Britain and Ireland" London, 1723]
fem. proper name, also the name of a butterfly genus. As a name, not much used in U.S. before 1950. It appears to have been coined by Swift c. 1711 as a pseudonym for Esther Vanhomrigh, who was romantically attached to him, and composed of elements of her name. He used it in private correspondence and published it in the poem "Cadenus and Vanessa" (1713).
The name Cadenus is an anagram of Decanus; that of Vanessa is formed much in the same way, by placing the first syllable of her sir-name before her christian-name, Hessy. [William Monck Mason, "History and Antiquities of the Collegiate and Cathedral Church of St. Patrick, Near Dublin," 1820]
As the name of a genus of butterflies that includes the Red Admiral and the Painted Lady, it dates to 1808, chosen by Danish entomologist Johan Christian Fabricius (1745-1808) for unknown reasons. He has no obvious connection to Swift, and the theory that it was intended for *Phanessa, from Greek phanes "a mystical divinity in the Orphic system" does no honor to his classical learning.
1872, trademark for an ointment made from petroleum and marketed by Chesebrough Manufacturing Co., coined from German Wasser "water" + Greek elaion "oil" + scientific-sounded ending -ine. Robert A. Chesebrough was of the opinion that petroleum was a product of the underground decomposition of water.
The name is of mixed origin, being derived from Wasser, water, and elaion [Greek in the original], oil (water-oil), and indicates the belief of the discoverer that petroleum, the mother of Vaseline, is produced by the agency of heat and pressure from the carbon of certain rocks, and the hydrogen of water. [The Monthly Review of Dental Surgery, February 1877]