During the 1990s when Apple first entered the external display market, they used the DB-15 video port. Product manuals of the time referred to the port as the “Macintosh video port” or later, the “Monitor port.”
An Apple Service Source document for the Macintosh LC Series/Quadra 605 (Macintosh LC, Macintosh LC II, Macintosh LC III, Macintosh LC 475, Macintosh Quadra 605) specifies the video standard as: “DB-15 monitor port for built-in video; DA-15 connector.”
This Apple Video Card Accessory (part number 513-0091-A) allowed “standard” VGA monitor to be used with a Macintosh computer.
Source: Apple