relative atomic mass (atomic weight), \(A_\text{r}\)

https://doi.org/10.1351/goldbook.R05258

The ratio of the average mass of the atom to the unified atomic mass unit.

See also: standard atomic weight

Sources:
Green Book, 2^nd ed., p. 41 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 990 (https://doi.org/10.1351/pac199668040957)