transversus abdominis vs ab

transversus abdominis and ab both are nouns.

Word	Noun	Adjective	Verb	Adverb
transversus abdominis	Yes	No	No	No
ab	Yes	No	No	No

As nouns, ab is a hypernym of transversus abdominis; that is, ab is a word with a broader meaning than transversus abdominis:

transversus abdominis: a flat muscle with transverse fibers that forms the anterior and lateral walls of the abdominal cavity
ab: the muscles of the abdomen

Other hypernyms of transversus abdominis include abdominal, abdominal muscle.

transversus abdominis (noun)	ab (noun)
a flat muscle with transverse fibers that forms the anterior and lateral walls of the abdominal cavity	the muscles of the abdomen