backstitch vs embroidery stitch

backstitch and embroidery stitch both are nouns.

Word	Noun	Adjective	Verb	Adverb
backstitch	Yes	No	Yes	No
embroidery stitch	Yes	No	No	No

As nouns, embroidery stitch is a hypernym of backstitch; that is, embroidery stitch is a word with a broader meaning than backstitch:

backstitch: an overlapping stitch made by starting the next stitch at the middle of the preceding one
embroidery stitch: a stitch made with thread and a threaded sewing needle through fabric or leather

Other hypernyms of backstitch include sewing stitch.

backstitch (noun)	embroidery stitch (noun)
an overlapping stitch made by starting the next stitch at the middle of the preceding one	a stitch made with thread and a threaded sewing needle through fabric or leather

backstitch (verb)	embroidery stitch (verb)
do backstitches