NeXT is the company Steve Jobs founded after he was booted from Apple in 1985. They originally made these extremely high end, high priced computers, but eventually moved to an all-software model.
It’s a historical device. Tim Berners-Lee used a NeXT Computer in 1991 to create the first web browser and web server, and John Carmack used a NeXTcube to build Wolfenstein 3D and the original Doom.
NeXt was eventually acquired by Apple in 1996 for $429 million. That brought Jobs back to Apple, and because of that I get to have an iPhone. Cool stuff.