skull practice vs skull session

skull practice and skull session both are nouns.

Word	Noun	Adjective	Verb	Adverb
skull practice	Yes	No	No	No
skull session	Yes	No	No	No

As nouns, skull practice and skull session are synonyms defined as:

skull practice (noun)	skull session (noun)
teaching strategy to an athletic team	teaching strategy to an athletic team
	a session (as of executives or advisors) to discuss policy or strategy or to solve problems or exchange ideas