1. 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.)
2. edible muscle of mollusks having fan-shaped shells; served broiled or poached or in salads or cream sauces
3. thin slice of meat (especially veal) usually fried or broiled
4. edible marine bivalve having a fluted fan-shaped shell that swim by expelling water from the shell in a series of snapping motions