Mass per time In physics and engineering, mass flow rate is the mass of a substance which passes per unit of time. [Wikipedia: https://en.wikipedia.org/wiki/Mass_flow_rate] Mechanics QUDT http://qudt.org/vocab/quantity#Masspertime Also known as loading. ODM2 Units Type Controlled Vocabulary ODM2 Working Group A vocabulary for describing the type of the Unit or the more general quantity that the Unit represents.