Chat
Middle English: shortening of chatter.
wiktionary
Abbreviation of chatter. The bird sense refers to the sound of its call.
Compare chit(“small piece of paper”), and chad. [1]
Origin unknown.
From thieves' cant.
chat (plural chats)
etymonline
chat (v.)
mid-15c., "talk idly, babble," short for chatter (v.). Meaning "to converse familiarly" is from 1550s. Sense of "flirt with, ingratiate oneself with" (later often with up (adv.)) is from 1898. Related: Chatted; chatting.
chat (n.)
1520s, "chatter, frivolous talk;" see chat (v.). Meaning "familiar conversation" is from 1570s. As a name for birds with chattering cries, 1690s. Chat show for what in U.S. is a talk show is attested from 1967. Chat room in the online sense is attested by 1994, from the days when AOL ruled the World Wide Web.
