Other forms: thimbles
A thimble is a device that protects your fingertips from being pricked by a needle. It's a good idea to use a thimble when you're sewing by hand.
When you sew with a needle and thread, you can wear a thimble on whichever finger you tend to use for pushing the needle through the cloth. Most thimbles are made of metal (originally they were made from leather) and fit like a small cup over your fingertip. The word thimble shares a root with the word thumb.