Maybe you've noticed a wine server at a nicer restaurant or in a movie wearing what looks like a large medallion around their neck. You typically can't miss it. It's large, shiny, and normally worn with a silver chain or a ribbon.
What might seem to be a large medallion is actually called a "tastevine" which is pronounced "Taht-vanN." It's a French word for "taste wine." And, yes, it is (or was) used to taste wine.
This shallow silver metal cup is faceted and convex. And, its original design was intended to be used in the low lighting of a wine cellar. The shiny metal, the facets, its convex shape and its shallowness were designed such that in low light, a small quantity of wine could be poured into it and provide the wine maker with a better view of the color and clarity of the wine.
Today, a tastevin is more of a Sommelier's (“suh-mel-yay”) badge of tradition. A bit of Sommelier bling. But, a Sommelier may still open a bottle of wine either at your table or at a Sommelier station, and pour just a splash of wine in their tastevin to sip it to ensure the wine is not flawed.
So, next time you see a wine server wearing this device around their neck, you'll know that originally it had a very useful purpose. But today, it's a bit more of a show-piece. Cheers!