"oil viscosity" refers to how thick or thin oil is. It describes the oil's resistance to flow. A high viscosity means the oil is thick and flows slowly, while a low viscosity means the oil is thin and flows quickly. Full definition
NOTE3: Do not think of oil viscosity numbers in terms of thicker or thinner... Flow rate is modified by means other than the how thick or thin it is. (mechanics.stackexchange.com)
The manuals for the 2015 - 2018 Pathfinder list SAE 0W - 20 as the recommended oil viscosity. (samarins.com)
By coming into our Los Angeles Toyota dealership and getting your filter changed, you can help maintain proper oil viscosity and extend the life of your Toyota. (hollywoodtoyota.com)