In Latin, what's the difference between Decus, Honos, and Honor?

My latin is a bit rusty but here's an attempt...
Decus means honor or dignity doesn't it? And then honos is like distinction. Honor on the other hand is like regard or dignity.

If I remember right, they all come from the same word and basically all mean the same thing, but it depends on what your talking about, which one you use.