[Ziro-]

argh....ehrmm....yea.....i think both owners of something should each be called an "Owner" but the word "co-owner" would be used to show that the person doesn't completely own it....like......

"Ryan W and LiquidIce are co-owners of that stripping club"

and

"Ryan W and LiquidIce are owners of that stripping club"

or

"Ryan W is co-owner of that stripping club."

but not

"Ryan W is owner of that stripping club. LiquidIce is co-owner." this would seem as if you're trying to imply that LiquidIce is nothing compared to Ryan W, because saying one of the first two things should mean the same thing.