When did CLI become TUI?

Am I just old? I missed it, and I feel like it happened in the last year or two. Or are they different? What's the difference between TUI and CLI? Does anyone else think the U in GUI is only there to let the acronym be pronounced as gooey? Does anyone pronounce CLI? How do you pronounce it? I don't pronounce it, FWIW. When will then be now?

Edit: in the sober light of day, the difference that several pointed out is clear. Thanks everyone for indulging my questions!