midterm examination vs exam

midterm examination and exam both are nouns.

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

As nouns, exam is a hypernym of midterm examination; that is, exam is a word with a broader meaning than midterm examination:

midterm examination: an examination administered in the middle of an academic term
exam: a set of questions or exercises evaluating skill or knowledge

Other hypernyms of midterm examination include examination, test.

midterm examination (noun)	exam (noun)
an examination administered in the middle of an academic term	a set of questions or exercises evaluating skill or knowledge