composition by weight
gravimetric composition

The material composition by weight is:

Its composition by weight:

Percent composition by weight is a serious matter in the U.S., where mixed nuts have been regulated by the Food and Drug Administration since 1977.

Magnesium alloys are referred to by short codes (defined in ASTM B275) that denote the approximate chemical composition by weight.

Following is a list of aluminium bronze wrought alloy compositions, by ISO 428 designations (proportional composition by weight; copper is the remainder by weight and is not listed):