What exactly is a 2.5D drawing?

I was asked to jot the all the lengths from a cad diagram of a drone and I made a normal drawing. With scale and all the lengths. My seniors amde fun of me for drawing it like a 12 year old. I probably deserves that. But I cannot find anything on 2.5 D drawings. Is it just the top view, front view, and side view seperated. And if it is that, a drone has many intricate parts that's not necessarily visible frone the outside. I cannot outline those parts in any of these views. So is it really optimal to draw these instead of drawing it like a 12 year old with every dimension on display?