Q From Jan Pearce: This question was posed on the US television programme, The Late, Late Show with Craig Ferguson, ‘Who is Luke and why does he have his own temperature?’
A I presume no good answer was given, which is why you’re turning to me? That’s the trouble with these smart lines, they’re fun for a moment but leave you unsatisfied and wanting more. As it happens, it’s an interesting question and I’ve spent a few intrigued minutes delving into the history of lukewarm.
The word has been spelled in all sorts of different ways down the centuries, including lew-warm, loo-warm (a necessity in our house), lewke-warm and luckwarm. The first part was mainly in dialect use and transmitted orally, so the spelling only settled down to our modern version in the eighteenth century.
Luke has, of course, nothing to do with the given name. It comes from an Old English adjective hléow that has modern relatives in Dutch and German. It may be linked to hlēo, shelter or lee, and also to another Old English word meaning debilitated that developed into lew, weak or wan. To be lukewarm is to be only weakly warm, tepid.
An odd sidelight is that from the thirteenth century, luke by itself could mean lukewarm, as could lew (the English Dialect Dictionary reported a century ago that it was then very widely used in various spellings throughout England, Scotland and Ireland). So you could argue that lukewarm means “warm warm”.