fastener UK /ˈfɑːsənə/US /ˈfæsənɚ/ noun2 •Something or someone that fastens.The mechanic replaced the damaged fastener.This type of fastener is resistant to corrosion. •Mechanically, any device that fastens; especially, a collective term for items such as screws, nuts, washers, clasps, bolts and the like. formsfasteners