surface density, \(\rho_{\text{A}}\), \(\rho_{\text{S}}\)

https://doi.org/10.1351/goldbook.S06167

Mass divided by area.

Sources:
Green Book, 2^nd ed., p. 12 (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 994 (https://doi.org/10.1351/pac199668040957)