preliminary exam vs preliminary examination

preliminary exam and preliminary examination both are nouns.

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

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

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

Other synonyms of preliminary exam include prelim.

preliminary exam (noun)	preliminary examination (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