battlement vs crenellation

battlement and crenellation both are nouns.

Word	Noun	Adjective	Verb	Adverb
battlement	Yes	No	No	No
crenellation	Yes	No	No	No

As nouns, battlement and crenellation are synonyms defined as:

battlement and crenellation: a rampart built around the top of a castle with regular gaps for firing arrows or guns

Other synonyms of battlement include crenelation.

battlement (noun)	crenellation (noun)
a rampart built around the top of a castle with regular gaps for firing arrows or guns	the action of constructing ramparts with gaps for firing guns or arrows
	a rampart built around the top of a castle with regular gaps for firing arrows or guns