crenellation vs crenelle

crenellation and crenelle both are nouns.

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

crenellation (noun)	crenelle (noun)
the action of constructing ramparts with gaps for firing guns or arrows	a notch or open space between two merlons in a crenelated battlement
a rampart built around the top of a castle with regular gaps for firing arrows or guns	one of a series of rounded projections (or the notches between them) formed by curves along an edge (as the edge of a leaf or piece of cloth or the margin of a shell or a shriveled red blood cell observed in a hypertonic solution etc.)