What is "specific weight"

The specific weight (also known as the unit weight) is the weight per unit volume of a material. The symbol of specific weight is γ (the Greek letter Gamma).

A commonly used value is the specific weight of water on Earth at 5°C which is 9.807 kN/m or 62.43 lbf/ft. National Council of Examiners for Engineering and Surveying (2005). Fundamentals of Engineering Supplied-Reference Handbook (7th ed.). Clemson: National Council of Examiners for Engineering and Surveying. ISBN 1-932613-00-5

The terms specific gravity, and less often specific weight, are also used for relative density.