Archimedes' principle
noun Physics.
the law that a body immersed in a fluid is buoyed up by a force (buoyant force) equal to the weight of the fluid displaced by the body.
British Dictionary definitions for archimedes' principle
Archimedes' principle
noun
a law of physics stating that the apparent upward force (buoyancy) of a body immersed in a fluid is equal to the weight of the displaced fluid