scallop: 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.)
curve: the trace of a point whose direction of motion changes
linolenic acid: a liquid polyunsaturated fatty acid that occurs in some plant oils; an essential fatty acid