"Onlar takım elbise giyerler."

So why isn't "takım elbise" written in the plural here? In this context, would people usually say this word in the singular when referring to the plural?

Out of curiosity, what does takIm elbise mean literaly?

is takim a noun? If so, why is this not following the compound noun construction, with the second one in possessive form? Just want to be clear....