Saybolt Seconds Universal (SSU) viscosity

A measurement of viscosity (resistance to flow)of a lubricating oil. The number of seconds needed for 60 milliliters of oil at a specified temperature to flow through a calibrated orifice. The viscosity number used for commercial aviation engine lubricating oil relates closely to the SSU viscosity of the oil at 210 ºF.

Aviation Maintenance Technician Handbook — Powerplant, p. G-24