luminous intensity, $$I_{\text{v}}$$

https://doi.org/10.1351/goldbook.L03647
base quantity in the system of quantities upon which SI is based.
Sources:
Green Book, 2nd ed., p. 4 (https://dev.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 979 (https://doi.org/10.1351/pac199668040957)