A scant, which I interpret to be sewing next to the drawn line of a corner square , say like on a snowball block. This takes into account the amount of fabric lost in the pressing fold as you press to the dark side or open. A scant is also interpreted as 1 thread away from the seam line for the same reason, but is harder to find without a drawn line as in a diagonal seam. When you sewing with a group, consistency is not good enough even though it works for you when you are making the whole project. The adding up of the one thread loss in every seam across a block will make your block too small to share.