I’ve spent the last two days in Agrigento, a town on the south coast of Sicily, and close to an impressive Ancient Greek temple complex known as the Valley of the Temples. While on my way there, I wondered: why do we call the areas to the side of our forehead temples?
First, let’s look at the origin of the word temple, as in a religious site. It comes from the Latin templum, but the exact origins of that word are a little less clear. It’s likely though that it stems from the Proto-Indo-European root *tem-, meaning to cut or separate, based on the idea of a space separated and set aside for religious worship.
This may have stemmed from the PIE *ten- meaning to stretch, perhaps referring to the stretched rope demarcating the site of a temple.
Temple, in a biological sense, is derived from the Latin tempus (side of the head), more than likely also derived from *ten-, as the skin there is stretched thin.
So the two words aren’t really very directly linked. Any suggestion otherwise would be a bit of a… stretch…