(1):
(n.) One who sifts flour or meal.
(2):
(n.) An instrument or machine for separating bran from flour, or the coarser part of meal from the finer; a sieve.
(3):
(n.) One who bolts; esp.: (a) A horse which starts suddenly aside. (b) A man who breaks away from his party.
(4):
(n.) A kind of fishing line. See Boulter.