or gram atom

noun Chemistry.

the quantity of an element whose weight in grams is numerically equal to the atomic weight of the element.

Origin of gram-atom

First recorded in 1895–1900
Also called gram-atomic mass, gram-a·tom·ic weight [gram-uh-tom-ik, -tom-] /ˈgræm əˈtɒm ɪk, -ˌtɒm-/. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019