preliminary exam vs prelim

preliminary exam and prelim both are nouns.

Word	Noun	Adjective	Verb	Adverb
preliminary exam	Yes	No	No	No
prelim	Yes	No	No	No

As nouns, preliminary exam and prelim are synonyms defined as:

preliminary exam and prelim: an examination taken by graduate students to determine their fitness to continue

Other synonyms of preliminary exam include preliminary examination.

preliminary exam (noun)	prelim (noun)
an examination taken by graduate students to determine their fitness to continue	an examination taken by graduate students to determine their fitness to continue
	a minor match preceding the main event