Owner 和owners 都是业主或者老板的意思，只是前者是单数，而后者则是复数，区别可以从以下例子看出：

There are many owners for this block, I am the owner of small shop, therefore many issues have to be discussed with others. 这个街区有很多业主，我是小店的老板，所以很多问题要和别人讨论。