abdominal aorta vs abdomen

abdominal aorta and abdomen both are nouns.

Word	Noun	Adjective	Verb	Adverb
abdominal aorta	Yes	No	No	No
abdomen	Yes	No	No	No

abdominal aorta (noun)	abdomen (noun)
a branch of the descending aorta	the region of the body of a vertebrate between the thorax and the pelvis
	the cavity containing the major viscera; in mammals it is separated from the thorax by the diaphragm