Example: The bottleneck in mail delivery is the process of sorting.
source: wordnet30
Chance; lot; destiny.(noun)
source: webster1913
A kind or species; any number or collection of individual persons or things characterized by the same or like qualities; a class or order; as, a sort of men; a sort of horses; a sort of trees; a sort of poems.(noun)
To separate, and place in distinct classes or divisions, as things having different qualities; as, to sort cloths according to their colors; to sort wool or thread according to its fineness.(verb)
source: webster1913
To join or associate with others, esp. with others of the same kind or species; to agree.(verb)