If you do piecework, it means you're paid based on each task you accomplish rather than the hours you labor. A farmworker paid in piecework might earn a dollar for each pound of blueberries they pick.
You can think of piecework as a job that pays by the piece, unit, or action. While many employers compensate workers by the hour or pay a yearly salary, others dole out wages based on how much work is accomplished. A seamstress who gets paid for each pair of pants that she hems is doing piecework. And if your neighbor pays you five cents for each dandelion you pull out of their lawn, you also do piecework.