oral exam vs oral examination

oral exam and oral examination both are nouns.

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

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

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

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

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