This word originated from the one and only Kaitlyn The Great. She was the first ever person to address a group of people all at once by a simple one word phrase "chat". Genius idea really, signalling to your companions that your upcoming words are directed at all of them not just a select few. Kaitlyn has been saying it since before you were born she's fr the OG.
"Hey Chat"
"Wacth out chat, there is shooting up ahead"
"Don't let me down chat, this is not a drill"