piece work
Work done and paid for by measure of quantity at a fixed rate, according to a previous estimate of value, i.e. at an agreed price per thousand for a certain quality of bricks laid in a specified manner, or, in the case of stonework, at a given price per perch, etc., in contradistinction to work done and paid for by the measure of time, or by lump sum. (Sturgis, 1900)