Q: The word o’clock is an oddball. Are there any more words in English where a contraction is at the beginning?
A: Yes, o’clock is an odd contraction, but it’s not unique.
Most of the contractions we use in contemporary English were formed by combining two words, with the final word shortened and the missing part replaced by an apostrophe, as in I’ll (I + will), they’re (they + are), and don’t (do + not).
The contraction o’clock is an exception, since the beginning word is the one that’s shortened. The o’ here is a shortening of the preposition of, and o’clock was originally of clock, meaning “of or according to the clock.”
In addition to o’clock, the element o’ appears in some Anglicized Irish surnames (O’Brien, O’Connell, O’Neil, etc.), where it stands for “descendant of.”
And sometimes the first part of an expression is contracted in colloquial writing, as with y’all (you + all), c’mon (come + on), and s’pose (for suppose).
In the past, it was more common to shorten the first part of a contraction or even both parts, as in ha’n’t (have + not), sha’n’t (shall + not), ’tis (it + is), ’twere (it + were), and ’twill (it + will).
And here are a couple of archaic three-word contractions—’twon’t (it + will + not) and ’twouldn’t (it + would + not)—along with one that’s still seen today, ne’er-do-well (never + do + well).
Some single words were often contracted in older English. In addition to ne’er for never, there was o’er for over and e’er for ever. And some single words are still contracted: forecastle is often written as fo’c’sle or fo’c’s’le, and boatswain as bos’n, bo’s’n, or bo’sun, though bosun is more common. And, as you know, madam is often contracted as ma’am.
Technically, the shortened part of a contraction is a “clitic”; it’s unstressed and normally occurs only in combination with another term. A contracted part at the beginning (like the o’ in o’clock) is a “proclitic” and one at the end (like the ’re in they’re) is an “enclitic.”
Some words that are now considered short forms of longer ones began life as contractions, with the first part replaced by an apostrophe: ’copter (from helicopter), ’cello (from violoncello), and ’gator (from alligator). Eventually the apostrophes dropped away.
Others words showed up first as shortenings (not contractions), but were later occasionally written with apostrophes: flu (from influenza), phone (from telephone), and quake (from earthquake).
Getting back to o’clock, the usage first appeared in the form of clok in the early 15th century, according to citations in the Oxford English Dictionary. The first OED example, which we’ve expanded, is from a 1419 proclamation by King Henry V, ordering reinforcements rushed to the British Army in Normandy during the Hundred Years War with France:
“let hem arraye and make hem redy in þe best wyse þat þey can or may, in alle hast, and come to Seint Dunstanes in þe Est, a Monday þat next comeþ, at eyghte of clok.” Cited in A Book of London English, 1384–1425, edited by Raymond Wilson Chambers and Marjorie Daunt (1931).
The term was also written variously as off clok, of clokke, of clocke, of clock, and oclock (as well as a kloke, a clocke, etc.) until the modern spelling emerged in the early 17th century:
“Well, ’tis nine o’clock, ’tis time to ring curfew” (from The Merry Devill of Edmonton, 1608, an anonymous Elizabethan comedy that was once attributed to Shakespeare).
As for the use of O’ in Anglicized Irish names, the OED describes it as “a prefix in Irish patronymic surnames” that indicates “descent from an ancient Irish family.” A patronymic is a name derived from a father or paternal ancestor.
The dictionary says the usage is derived from ó, Irish for a grandson or descendant, and the “apostrophe probably derives from the Irish length-mark” over ó. The mark, a síneadh fada, indicates a long vowel. So O’Brien is an Anglicized version of the modern Irish Ó Briain and the classical Irish Ua Briain.