Oil

1) A fatty or greasy liquid obtained from plants, animals or minerals used for manufacturing. 2) A lubricant used to reduce wear in machines. 3) Substance which, along with greases and other petroleum-based products, is used for quenching in hardening and tempering and as a corrosion-preventing agent. The re­quirements which may be detailed in specifications or quenching oils are viscosity, acid value, saponification value, flash point, loss in heating (volatility) and thermal conductivity. Such oils should also be highly refined and thus free from un­stable constituents so as to improve the resistance of the oil to oxidation.