"Wooden. 15 inches diameter. Holds 4 quarts. 2 lbs." This is an advertisement about a kind of bowl. What does "Holds 4 quarts" mean ?
A quart is a unit of measure for volume. It is either a little bigger (UK) or smaller (US) than a liter, depending on which nation's quart they meant.
A US gallon is 3.78 liters. A quart is 0.25 (one quarter) of a gallon.