difference between `slang and colloquial'

[viet_ghat]

What is the difference between `slang word' and `colloquial'?

Could anyone explain it?

[Casiopea]

From A Dictionary of Slang,

Change in terminology
Expressions previously listed as colloquial (colloq) are now indicated as informal {Informal} in keeping with the notation standards set by The New Oxford Dictionary of English. Informal or colloquial expressions are not slang, but words and phrases accepted in ordinary speech and familiar conversation. They are not accepted as formal or literary.

Hope that helps.