An iMac feature that lets the screen function as an external monitor for another computer. Thunderbolt-based iMacs starting in 2011 can only be a Target Display Mode (TDM) screen for computers ...

It found one of those in the late 2000s and early 2010s with target display mode, which was a useful and short-lived feature. Target display mode allowed for a compatible iMac to be used as an ...