by weight
Determined by or according to how much something weighs, as opposed to some other measurement (e.g., by size or volume). To get a better value, I always steer clear of prepackaged produce and buy it by weight instead.
by weight
According to weight rather than height, volume, or some other measure. For example, In Europe bread often is sold by weight rather than by the loaf. [c. a.d. 1000]
by weight
According to weight rather than volume or other measure.