1. In joinery, a projection (tongue) on the edge of a board which fits into the groove of another board, as in a tongue and groove. Also called a spline. 2. To produce a featheredge.
1. In joinery, a projection (tongue) on the edge of a board which fits into the groove of another board, as in a tongue and groove. Also called a spline. 2. To produce a featheredge.