This is the 1223rd most frequent Russian word.
масло
Butter or oil.
Here, 'масло' is used to mean 'butter', a dairy product often used as a spread or cooking ingredient.
Я намазал хлеб маслом.
I spread butter on the bread.
In this sentence, 'масло' refers to 'oil', specifically engine oil used for lubrication in machinery like cars.
В двигателе моего автомобиля закончилось масло.
The oil in my car's engine ran out.
Here, 'масло' means 'oil' used in the context of oil paints, a medium for creating artwork.