The term 'knitting tool' can be summarized by the crossword solution 'NEEDLE, ' which is a six-letter word. Needles are an essential tool for knitting, as they are used to create loops of yarn that are then interlocked to form fabric. Needles come in a variety of sizes and materials, such as plastic, metal, and bamboo. They can also be straight or circular, depending on the type of knitting being done.