This post was inspired by my friend Richard Peej's Facebook post. He put up a picture of a carpentry joint (I don't know why, but who am I to judge people's odd hobbies?) Soon others added images of a marijuana joint, Sunday joint and an elbow joint being put to good use (er, yes that last one was me)
Other uses for the word include a place to meet someone for a drink, something done in partnership (eg jointly writing a book) part of a book cover, cutting up a carcass for food, held or belonging to more than one person (joint account) the contrivance by which two artificial things are joined together (that's something to do with plumbing, I think) the part of a stem from which a leaf grows, the cement bit between bricks and to prepare something ready to be joined to something else.
If I've missed any, please let me know - that way this post will be a joint effort.