Meaning

noun the branch of engineering that deals with the use of computers and telecommunications to retrieve and store and transmit information

originEquivalent to it + -s (possessive marker). From the earlier form it's (it + -'s), which is now considered nonstandard. Began to displace his as the possessive of the neuter pronoun in the Middle English period; had fully displaced it by the 1700s.

Etymology from Wiktionary, CC BY-SA 3.0