Rhyne is a fancy word for the little groove that you see on some things, like a spoon or a fork or even a knife. It's like a tiny little ditch or channel that's put there on purpose.
Do you ever notice how sometimes when you scoop up some soup or ice cream with a spoon, some of it drips off the sides? That's because of gravity, which is the force that pulls things down.
But the rhyne actually helps because it gives a place for the soup or ice cream to stay instead of dripping off the edge. So it helps keep your food on the spoon and not on the table or on your clothes!
It's also helpful when you're using a fork or a knife to cut something because it helps the food to not slide around too much.
So next time you see a rhyne on your utensils, remember that it's there to help you eat and not make a mess!