"Cherry MX Red" is a kind of switch. Not the official name, really, but the colour of the key stem. For "Cherry MX" switches, there is a different colour for each type of MX switch.
The "Cherry MX Red" switch has linear resistance - no tactile feedback. It is like the "Cherry MX Black" but the spring is not as hard.
For more info, I refer you to the Geekhack Wiki topic. Click on the link above. Or use the search function and read up. There is a wealth of information about keyboards with Cherry switches already written on this forum.