Fasten/ˈfæsn/ Definition 1 of 4Pro Tip 1/3Safety First Fasten's most common use relates to safety measures, such as seatbelts and helmets. Please fasten your helmet properly. Pro Tip 2/3Physical Connection Use fasten when referring to physically joining objects, often implying a strong bond. Fasten the boards with nails to make the shelf. Pro Tip 3/3Everyday Objects Fasten applies to daily tasks, like clothing or assembling items, and is practical in nature. Could you help me fasten this bracelet?