Slack 💬
Slack: Originally given the codename Linefeed, founder Stewart Butterfield came up with Slack on 14th November 2012. He would send a tweet that revealed he also created a backronym from the word: Searchable Log of All Conversation & Knowledge:
Yes. November 14th, 2012 (previous codename was "linefeed"):
— Stewart Butterfield (@stewart) September 27, 2016
Re https://t.co/GbFbiofkWS pic.twitter.com/mhdkWk16o2
In an interview Butterfield said: “I was really wedded to the name (Linefeed) and it was not really popular internally. There was a bunch of criteria we had: that we wanted it to be a regular English word, we wanted people to be able to spell it if we said it, we had to be able to get the trademark and we had to be able to get the domain. There’s the negative connotations: slacker, slacking off, but there’s also these positive connotations: to pick up the slack or to cut me some slack.”
Source: Tweet by Stewart Butterfield | Oxford English Dictionary