Wiktionary
piece work
alt. work that a worker is paid for according to the number of units produced, rather than the number of hours worked; work done and paid for by the piece or by the job. n. work that a worker is paid for according to the number of units produced, rather than the number of hours worked; work done and paid for by the piece or by the job.
Wikipedia
Piece work
Piece work (or piecework) is any type of employment in which a worker is paid a fixed piece rate for each unit produced or action performed regardless of time.