Just like it says. It is a single color print
This is 2 or more colors printed separately to create the art.
That involves printing the four basic print colors — cyan, magenta, yellow and black (CMYK) — in fine, half-tone dots. Unlike a typical four color print, in which the colors are clearly divided, four color process involves printing wet-on-wet with colors overlapping so they mix and create thousands of different tones.