I was standing over the sink today, wanting to wash my hands and busy setting the water temperature so that it was lukewarm, when I started to think: What the hell is LUKEwarm? Luke? As in Matthew, Mark, John, etc.? Where does Luke come from ... and is the word just a regionalism for "tepid."?
Turns out not. Lukewarm comes from the Middle English (and from the elderly French language that visited England circa 1066), and probably is related to the old high German "Iao," which meant moderately warm, and the Latin "calere." It is related to "lee," which had to do with being warm in Old English, and now means the side of a ship that is out of the wind, protectect from the storm.
Actually, well protected from the snowstorm outside, but which storm was all-too visible outside the window over my kitchen sink, my interest in the whole question of "lukewarm" started to lack conviction. Become halfhearted. After all, pretty soon I had to shovel my sidewalk. My interest in doing so was tepid at best.