According to my mother, the crimped or crenellated edge of pies is not just decorative: the little indentations allow the pastry to “give,” so that the edge does not crack and crumble while it bakes. To create such a crenellated edge, a rimmer is often used, a device that clearly derives its name from its being pressed around the rim of the pie tin. Further back in history, the word rim evolved from the Old English rima, a word meaning ridge or raised edge, though the edge in question did not have to be a circular one. Tooth-rima, for example, was an Old English compound meaning gums, that is, the raised edge of flesh that holds your teeth in your head. In time, however, rima came to mean circular edge, a shift in meaning that probably occurred because of the frequent application of rima to the horizon of the earth: daeg-rima, meaning day-rim, was used to refer to the horizon on land, while sae-rima, meaning sea-rim, was used to refer to the horizon while at sea. These natural “rims” or horizons extend around us like circles, a fact not lost on the speakers of Old English, who began to reserve the use of rima or rim for other sorts of circular edges, especially those of plates, cups, and bowls.