If a farmer offers to introduce you to her kid, you might not know if she means her child or her baby goat.
A kid is a child, informally, and it's also a young goat. Sometimes the word kid means a kind of soft leather made from goat skin. When kid is used as a verb, it means to tease or jokingly deceive someone — to kid them. Some sticklers for formality object to using kid to mean "child," but that meaning has been around since the 1590s. The "teasing" definition of kid comes from the sense of "treat like a child."