'Your' can be treated like an adjective. Ex. -Your house is very big. -This is your pen. 'Yours' can be treated like a noun (although it's a pronoun). It takes place of the original noun, similar to 'it'. -That pen is mine. Where is yours? (ie. "Where is your pen?") "Your's" is not a word.

There is no "your's" as a separate word, although some write "yours" that way. The pronoun "yours" means that belonging to you. "Your" is the possessive pronoun. It's like the relationship between my and mine.