single crochet vs crochet

single crochet and crochet both are nouns.

Word	Noun	Adjective	Verb	Adverb
single crochet	Yes	No	Yes	No
crochet	Yes	No	Yes	No

As verbs, crochet is a hypernym of single crochet; that is, crochet is a word with a broader meaning than single crochet:

single crochet (noun)	crochet (noun)
the basic crochet stitch	needlework done by interlocking looped stitches with a hooked needle

single crochet (verb)	crochet (verb)
make by single stitching	make a piece of needlework by interlocking and looping thread with a hooked needle
	create by looping or crocheting