It has long been one of my pet peeves that, as a discipline, physicists seem to be way better than mathematicians at giving things cool and useful names. This disparity appears to have grown in the last few decades, as physicists have started naming quarks (charm, strange, flavor, red/blue/green) and dark matter (WIMPs and MACHOs). I hang my head in shame when I realize that the average mathematician would probably have named dark matter particles ‘pseudo-massive quasi-particles’ and called it a day. Mathematicians, of course, can’t even stop giving things the same name – bundle, sheaf, stack, gerbe (french for bundle, sheaf or stack) – or just tacking on more prefixes to an existing name… I’m looking at you, deformed pre-projective algebras.
What mathematical term has always bothered you, for the uselessness, obtuseness or unfortunateness of its name? I’m hoping to see what has always rankled other people.
For me, I’ve always been bothered by the Lyusternik-Schnirelmann category, which is the smallest number of contractable open subsets that cover a given topological space. Now, I believe in naming things after people, but why do it when the underlying concept is so straightforward? The name hasn’t aged well, either; in modern times few mathematicians think of a positive integer when they hear ‘category’. The term is particularly frustrating when compared to the nearby concept of cup-length, which you might reasonably guess is the length of the longest non-trivial word in the cup-product.