It’s an obviously modern word, tranquillize, isn’t it? Actually, no. I recently met it, used in a general sense, not that of shooting sedative darts into Sunderbans tigers, in Lady Susan, an early work by Jane Austen. Curious, I consulted my Oxford dictionary — which dates its first appearance not even to the 1790s but 1623.

Likewise rationalist, someone who puts reason above god as a source of authority. I’d have ascribed it, at earliest, to Europe’s 18th-century Enlightenment. Not so: in the 1640s, with England in religious and intellectual ferment, a pamphleteer wrote of “a new sect sprung up...the Rationalists”, who accepted “what their reason dictates to them in Church or State, until they be convinced with better.”

That road to verbal innovation is common: the new fact gets a new name. Most of today’s scientific nomenclature was born this way. The 19th century gave us chloroform and isothermal; the 20th radar, positron and the internet (which in turn generated blog, a brand-new word for a brand-new activity). The mysterious vocabulary of today’s high finance, bristling with such modern gems as disintermediation, mostly reflects practices that are equally modern.

Wider linguistic novelty often arrives merely as old words get new meanings. Flat was around long before it meant apartment; 200 years ago, it was, among other things, slang for a fool. But new words are always being created even for old realities. The mob has been with us since at least Roman times. Not so its name.

Pardoned outlaws

In the 1680s a London political club started talking of the mobile vulgus, Latin for the easily-swayed common people, then shortened it, and only then mob was born. A few decades later, The Spectator was calling the word “one of many formerly slang which are now used by our best writers and received, like pardoned outlaws, into the body of respectable citizens.”

Such close dating is rare. Oxford’s dictionary whizzes record the first written use they have found, but their database has constantly to be revised. A few words, however, can be dated very precisely: Captain Boycott was an Irish land-agent who got that treatment — for his oppression of his employer’s tenants — in 1880. But who first used boycott or any other novel word? Very rarely can we be sure. First use in print does not mean first use; and even if its date is definitively known, the fact that some word is first, or even only, found in the works of a given author — Shakespeare, often — is no proof that he invented it.

Revived or coined?

A few words can be precisely attributed. Matriarch is 400 years old. But it owes the firm place that it and its derivatives now hold in our language almost entirely to Robert Southey, who revived it (indeed coined it, supposed one 19th-century expert) two centuries later as a humorous term for the wife of Job, one of the biblical patriarchs. A colleague of mine on The Economist, Norman Macrae, dreamed up stagflation for the conjunction of sharp inflation with a stagnant economy. But even so recent a word as blog is of disputed parentage. It’s a wise word that knows its own father.

And no word can be sure of its future. Many hundreds — some say thousands — are born each year. Few survive long. I myself once fathered two: dimbleburble, after British broadcasting’s best-known commentators, the two Dimbleby brothers; and dollytime, the hour around 5 pm when a host of young women (mark the Seventies British slang) crowd from their offices to fill delightfully (this was in Tokyo) the city streets. Alas, the world was too busy, watching its TV screen maybe, or the young women, even to notice.