The Collaborative International Dictionary
Pitching piece
Pitching \Pitch"ing\, n.
The act of throwing or casting; a cast; a pitch; as, wild pitching in baseball.
The rough paving of a street to a grade with blocks of stone.
--Mayhew.-
(Hydraul. Eng.) A facing of stone laid upon a bank to prevent wear by tides or currents.
Pitching piece (Carp.), the horizontal timber supporting the floor of a platform of a stairway, and against which the stringpieces of the sloping parts are supported.
Wiktionary
pitching piece
n. (context carpentry English) The horizontal timber supporting the floor of a platform of a stairway, and against which the stringpieces of the sloping parts are supported.