The term 'FASTENS (TO)' is a crossword solution that can be broken down into two words: 'FASTENS' and 'TO'. The word 'FASTENS' is a verb meaning TO secure or attach something firmly in place. The word 'TO' is a preposition that indicates the direction of an action. Together, the two words form the phrase 'FASTENS TO', which means TO attach something firmly in place. This phrase is often used when referring TO the act of affixing something, such as a stamp or label, TO an object.