Système International d'Unités, the international system of units established in 1960 and based on seven base units for the quantities: length, time, mass, electric current, thermodynamic temperature, amount of substance and luminous intensity.
Source:
Green Book, 2nd ed., p. 69 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)
See also:
PAC, 1996, 68, 957. 'Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)' on page 995 (https://doi.org/10.1351/pac199668040957)