Bolter \Bolt"er\, n. A kind of fishing line. See {Boulter}. Bolter \Bolt"er\, n. One who bolts; esp.: (a) A horse which starts suddenly aside. (b) A man who breaks away from his party. Bolter \Bolt"er\, n. 1. One who sifts flour or meal. 2. An instrument or machine for separating bran from flour, or the coarser part of meal from the finer; a sieve.