oral examination vs oral exam

oral examination and oral exam both are nouns.

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

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

oral examination and oral exam: an examination conducted by spoken communication

Other synonyms of oral examination include oral, viva, viva voce.

oral examination (noun)	oral exam (noun)
an examination conducted by spoken communication	an examination conducted by spoken communication