radian

https://doi.org/10.1351/goldbook.R05036
SI derived unit of @[email protected], \(\text{rad} = 1\).
Sources:
Green Book, 2nd ed., p. 72 [Terms] [Book]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 988 [Terms] [Paper]