Salt or pepper shaker I'm thinking. The thick bottom is a just a design concept by the maker I'm guessing? Maybe to give it a heavy base, so it can't be knocked over so easily and roll off the table? I think it comes from the 1940s all the way to the early 60's. Sold through your five & dime stores back in the day? Maybe worth something to someone who also has only one other, so they could complete a set of two?. The silver value wouldn't be but a small amount.