noun
: a bolt that has a nut with pivoted flanged wings that close against a spring when passed through a constricted passage and open after emerging and that is used to fasten objects to thin or hollow walls
noun
: a bolt that has a nut with pivoted flanged wings that close against a spring when passed through a constricted passage and open after emerging and that is used to fasten objects to thin or hollow walls
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012