Not really. Only after your comment i realized that it stands for any key at all. I never actually thought what it means before.
Unfortunately, for me when I googled that exact phrase just now it gives a "Featured Snippet" saying it means "the beginning of a line", which is about regexen and and also only sort of right in that context. The wikipedia page is the first real result though.
Edit: I was spelling caret wrong. oops.