Engine oil grades

[Nebby]

Can someone tell me what the grades mean ie 5w 30, 10w 40, 20w 50. What does the 5 stand for and the 30 and so on for each.

I know ones viscosity but don't know which one.

Thanks.

[AdeTuono]

Ever heard of Google?

http://en.wikipedia.org/wiki/Motor_oil