Means color number. It’s basically a lookup table to simplify getting the RGBA for common colors.
# Primary Colors
var red = ColorN('red')
print (red) # prints 1,0,0,1
var blue = ColorN('blue')
print (blue) # prints 0,0,1,1
#Color blend
var purple= ColorN('purple')
print (purple) # prints 0.63,0.13,0.94,1