prickly pear cactus vs prickly pear

prickly pear cactus and prickly pear both are nouns.

Word	Noun	Adjective	Verb	Adverb
prickly pear cactus	Yes	No	No	No
prickly pear	Yes	No	No	No

As nouns, prickly pear cactus and prickly pear are synonyms defined as:

prickly pear cactus and prickly pear: cacti having spiny flat joints and oval fruit that is edible in some species; often used as food for stock

prickly pear cactus (noun)	prickly pear (noun)
cacti having spiny flat joints and oval fruit that is edible in some species; often used as food for stock	round or pear-shaped spiny fruit of any of various prickly pear cacti
	cacti having spiny flat joints and oval fruit that is edible in some species; often used as food for stock