The key marked ` is often set as a "dead key" on European keyboard layouts -- typically the layouts where the accent isn't commonly used, but will be needed for typing people and place names, or the occasional foreign word.
With a Danish Mac layout, to type ` I press it then press space. To type è, ì etc, I press `, then press the vowel. Similarly I can use the keys marked ¨ ^ and ´. (The Danish letters æ, ø, å have their own keys, since they are used very frequently.)
So, I would never call it "backtick", since it is a grave accent.
It pisses me off to no end when software uses keyboard shortcuts like Ctrl+anything, unless it's using ASCII control characters (e.g. vi, emacs). Every *nix GUI toolkit knew this until the year-of-desktop-Linux crowd insisted on slavishly imitating every Windows mistake.
With a Danish Mac layout, to type ` I press it then press space. To type è, ì etc, I press `, then press the vowel. Similarly I can use the keys marked ¨ ^ and ´. (The Danish letters æ, ø, å have their own keys, since they are used very frequently.)
So, I would never call it "backtick", since it is a grave accent.