The throat is the shortest dimension across the inner corner of an angled structural member, such as a wooden knee or a curved brace. In timber framing and boatbuilding, the thickness of the throat dictates the overall strength of the piece against bending forces. If a knee is cut with too deep a curve, the throat becomes too thin and creates a weak point.
Heard on the job
Make sure the throat on that oak knee is at least six inches thick to support the deck load.