No matter the size of the drawing, it is depicted in the same proportions as the actual object that is the subject of the drawing.
It means that the distances are all relative to each other - equal.
If you hand draw a map for a friend, you know, with a main road and a couple of streets, it's not usually "to scale." You might draw two streets different lengths, whereas they might be the same length in reality. If you look at a proper map, it's always to scale. Might be that 1 inch equals a mile, for example.
proportion!! THANK YOU, amblessed,. I couldn't come up with that word for the life of me last night... whew.