In a Word: Lukewarm: Who Is Luke, and How Warm Is He?

Senior managing editor and logophile Andy Hollandbeck reveals the sometimes surprising roots of common English words and phrases. Remember: Etymology tells us where a word comes from, but not what it means today.

One of the things I love about the English language is how malleable, innovative, and democratic it is. If I find the need and I’m feeling creative, I can piece together existing word parts and create an entirely new word; if I do it well, its meaning will be apparent without explanation even though it didn’t even exist moments before. That word then has a chance of becoming “a real world” if other English speakers recognize its usefulness and start using it themselves.

That’s how the language grows and changes, for better or worse. And it happens all the time.

But despite this almost weed-like lexical expansion, sometimes a word from much older times lodges itself into the language, in either a phrase or compound, and doesn’t budge. It fossilizes there, even while the same word in its root form disappears into obsolescence. Words like the were in werewolf, the cob in cobweb, and the subject of today’s column: the luke in lukewarm.

The first half of lukewarm traces to the Middle English leuk, which meant “moderately warm, tepid,” or, not to put too fine a point on it, “lukewarm.” Etymologically, lukewarm is a redundancy. Eight centuries ago, English speakers wouldn’t refer to a pot of warmish water as lukewarm, but just as leuk.

To trace the root back further in time requires some speculation. It might come from an unrecorded variant of the Old English hleowe, an adverb meaning “warm”; this would explain why in the 1300s we find examples of both luke-warm and lew-warm.

It could also be related to the Old English hleo, meaning “shelter.” This is the root of the words lee (again, “shelter”) and leeward. On a ship or island, the leeward side is opposite the windward side. The leeward side is therefore sheltered from the wind, hence the name; but because it is sheltered, it is also warmer than the windward side, though not necessarily warm. Much like the relationship of lukewarm water to warm and cold water.

Luke was sometimes employed in other compound words, like luke-hearted and luke-hot, but not for several centuries. They, along with the adjective luke on its own, have disappeared from the language. Only lukewarm remains.

(The proper name Luke is unrelated, in case you were wondering. It’s a contraction of the Latin Lucanus, literally “of Lucania,” a geographic area in southern Italy, now called Basilicata, between the Tyrrhenian Sea and the Gulf of Taranto.)