color gamut

The set of colors a specific device (a display or a printer) can actually produce.

A device's color gamut is the subset of physically producible colors given its own emitters (a display) or inks (a printer). Two devices with different gamuts can render the identical stored $(R,G,B)$ triple as two visibly different colors, since RGB itself is device-dependent -- and an RGB display's gamut and a CMYK printer's gamut are different shapes entirely, which is the real reason a photo edited on-screen can shift once printed, independent of any calibration error.