Meaning

noun 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 obse

noun a notch or open space between two merlons in a crenelated battlement

verb supply with battlements

originFrom Old French crenel ( > modern French créneau), diminutive of cren (“notch”).

Etymology from Wiktionary, CC BY-SA 3.0