(~s)
1.
A ~ is a substance which you put on the surfaces or parts of something, especially something mechanical, to make the parts move smoothly.
Its nozzle was smeared with some kind of ~.
...industrial ~s.
N-MASS
2.
If you refer to something as a ~ in a particular situation, you mean that it helps to make things happen without any problems.
I think humor is a great ~ for life.
N-COUNT: usu supp N