What is TR in UK crochet?
Treble crochet in UK terms or double crochet in US terms is a taller stitch than double crochet (UK). It is around twice as tall as double crochet which means that your work will grow more quickly with this stitch, in the same way as a wall would grow more quickly if you used taller bricks.
What is single crochet in UK terms?
A US single crochet (UK double crochet) has only one yarnover after inserting it into the stitch but has two loops on the hook after pulling up a loop (hence, double in UK crochet terms).