Small square

ONE

Think of the lowest whole number that can represent a single unit or a tiny block in a grid.

"Small square" hints at a tiny box shape, but it’s also a playful nod to the word "one." In crosswords, "square" can refer to the individual boxes in the grid, and "small" suggests the simplest form—just a single box. The answer is "ONE" because it’s the number you’d write in one square, and it sounds like "won," reinforcing the idea of a single unit.