BOLT, an O. Eng. word (compare Ger. Bolz, an arrow), for a “quarrel” or cross-bow shaft, or the pin which fastened a door. From the swift flight of an arrow comes the verb “to bolt,” as applied to a horse, &c., and such expressions as “bolt upright,” meaning straight upright; also the American use of “bolt” for refusing to support a candidate nominated by one’s own party. In the sense of a straight pin for a fastening, the word has come to mean various sorts of appliances. From the sense of “fastening together” is derived the use of the word “bolt” as a definite length (in a roll) of a fabric (40 ft. of canvas, &c.).
From another “bolt” or “boult,” to sift (through O. Fr. buleter, from the Med. Lat. buretare or buletare), come such expressions as in Shakespeare’s Winter’s Tale, “The fann’d snow, That’s bolted by the northern blasts twice o’er,” or such a figurative use as in Burke’s “The report of the committee was examined and sifted and bolted to the bran.” From this sense comes that of to moot, or discuss, as in Milton’s Comus, “I hate when vice can bolt her arguments.”