In crochet basic stitches are called different things. For example a single crochet in America is called a double crochet in the UK, a double crochet in America is called a treble crochet in the UK, etc. I think (and this is a guess) that they are both consistent, with the American versions named after the height of the stitch and the UK version named after the number of loops on the crochet hook.
When did they diverge?
Crochet feels like an old craft that must have been commonplace around the time that Europeans settled America. Describing crochet stitches must have been similarly commonplace so what would cause these two usages to develop - is there a history of crochet terms that would chart this out?