basis weight; ream weight
Technical term in paper manufacturing and printing; refers to the weight of a ream (typically 1000 sheets) of paper, used to indicate paper thickness or density.
The basis weight of this copy paper is 70 kg.
The higher the basis weight, the thicker the paper.
Compound of 連 (ream) and 量 (weight/quantity). The exact historical derivation is uncertain, but the term is conventionally used in the paper industry.