In Unity terms, there're "world coordinate" and "screen coordinate".
In RPG Maker terms, they're "map coordinate" and "screen coordinate".
The difference is, the map coordinate is the actual coordinate of the game object in the game. Like where the characters/sprites located in the map. Screen coordinate is the coordinate where it will be drawn in your screen,
As Theo said map coordinates are where its located on the map. Screen coordinates is directly on the screen, a good example of that would be for example a HUD can be displayed at x: 0 and y:0, that will show the HUD at the top left of the screen no matter where your character is on the map but if it was on the map you would have to walk your character to the top left of the map which may involve some scrolling before you get there.
One more notable difference is that map coordinates refer to the tile your character is assigned to. If your character moves, their map coordinates immediately change to those of the tile they are moving towards, with no transition.
The screen coordinates on the other hand are measured in pixels and reflect your characters position more precisely if needed. Apart from HUDs those can also be utilized to check if your characters collide with projectiles or other objects on the screen for example.