WEDGE

[noun] [C] - a piece of metal, wood, rubber etc. with a pointed edge at one end and a wide edge at the other, which is either pushed between two objects to keep them still or forced into something to break pieces off itPush a wedge under the door to keep it open while we're carrying the boxes in.Pieces of stone can be split off by forcing wedges between the layers.(figurative) Auntie Ann put a huge wedge (= triangular-shaped piece) of fruit cake on my plate.