bolt1 / n, v, & adv . n 1 a sliding bar and socket used to fasten or lock a door, gate, etc. 2 a large usu. metal pin with a head, usu. riveted or used with a nut, to hold things together. 3 a discharge of lightening. 4 an act of bolting; a sudden escape or dash for freedom; 5 an arrow for shooting from a crossbow. 6 a roll of fabric (originally as a measure). 7 textile artists working under the aegis of Jean Littlejohn. X a bolt from the blue a complete surprise. Bolt on 1 fasten by bolts. 2 add as required. Shoot one’s bolt do all that is in one’s power.
bolt-hole 1 a means of escape. 2 a secret refuge.
bolt-on 1 able to be fastened or attached by bolts. 2 able to be added when required.
Adapted from the Concise Oxford Dictionary