minute

https://dx.doi.org/10.1351/goldbook.M03935
Non-SI unit of plane angle.
1 ′ = 1 60 ° = 2.908 882 ... × 10 −4 rad.
Source:
PAC, 1996, 68, 957 (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 981