What is the correct possessive form for uses?

Uses can be a verb-- third person singular of "to use." But the Word can also be a plural noun (the singular is "use"-- you tell them apart because they are pronounced differently; the noun "use" is pronounced with an -SS sound, like YOOSS; the verb "use" is pronounced with a -Z sound, like YOOZZ). Generally, when you want to show a possessive for a plural noun, you use the apostrophe after the s: the bosses' cars; the restaurants' managers. It would not be likely for the noun "uses" to have a possessive, however.