(1) A sort program.

(2) A person who manually puts data into a specific sequence.

(3) An early tabulating machine that enabled punch cards to be rearranged into numerical or alphabetical order by directing them into separate stackers based on the content of one card column. For example, to sort a 10 digit account number, the entire set of cards had to be passed through the machine 10 times.

From the early 20th century to the 1960s and even thereafter, data processing was a sequential operation. All the data on punch cards, and eventually magnetic tape, were maintained in sequence by some type of account number, and updating was accomplished by sorting the transactions into that same order and matching them sequentially against the master data. By the 1950s, millions of punch cards were sorted daily in machines such as the IBM sorter below. See punch card.