sorter

Etymology

sort + -er

noun

1. A person employed to sort.
   But soon one notices, first in ones and twos, and then in larger groups, men who are very much alive at this hour in the morning, the sorters for the Caledonian, and Edinburgh sections of the "Down Special"; mail is piled high on the platforms, and the postal men glance occasionally towards the platform intermediate signals. By this time the calling-on arm is pulled off, and a few minutes later in comes the train, unannounced by the loud-speakers, to the mystification of many travellers. 1948 May and June, O. S. Nock, “Scottish Night Mails of the L.M.S.R.—3”, in Railway Magazine, page 157
2. A machine or algorithm that performs sorting.