Your neck is the part of your body that connects your head and your shoulders. Your neck, with help from your spine, supports the weight of your head.
It's also thanks to your neck that you can turn your head in all directions (except, of course, directly behind you). Your sweaters and t-shirts have necks too, the holes meant for your head and neck to slide through. In geography, a neck is a long, thin peninsula, a stretch of land that looks neck-like on a map. And to neck is to kiss amorously.