noun
Physics term for mass, as distinct from weight. Used in scientific and technical contexts.
物体の質量は場所によって変わらない。
The mass of an object does not change depending on location.
noun
quality and quantity
Refers to both the quality and the quantity of something, often used in set phrases like 質量ともに (in both quality and quantity).
See also: 質量ともに
この製品は質量ともに優れている。
This product is excellent in both quality and quantity.