The Spanish verb 'cuadrar' (meaning 'to square') comes from the Latin verb 'quadrare', which meant 'to make square'. The Latin 'quadrare' was derived from 'quadrum' meaning 'square', which itself came from 'quattuor' meaning 'four' - a logical connection since a square has four equal sides.

Several common Spanish words share this etymology, including: 'cuadrado' (square), 'cuaderno' (notebook - originally referring to a sheet of paper folded into four), 'cuadra' (city block - referring to the square shape of city blocks), and 'escuadra' (square tool for measuring right angles).

Many English words related to 'four' or 'square' share this Latin root, including: 'quadrant' (a fourth part of a circle), 'quadrilateral' (a four-sided shape), 'squad' (originally a square formation of soldiers), and 'quarter' (one-fourth). The word 'square' itself comes from the same Latin root 'quadrum'.