scallop, crenation, crenature, crenel, crenelle -- (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.))
crenel, crenelle -- (a notch or open space between two merlons in a crenelated battlement)