The Spanish word 'escuadra' (meaning 'square tool') comes from Vulgar Latin '*exquadra', which meant 'square tool'. This Vulgar Latin term was derived from the Latin verb 'exquadrare' meaning 'to make square', which was formed by combining the prefix 'ex-' (meaning 'out') with the verb 'quadrare' (meaning 'to make square').

The evolution from Latin to Spanish shows a typical pattern where the Latin 'ex-' prefix evolved into 'es-' in Spanish, and the '-quadr-' root maintained its association with the concept of squares and right angles.

Several common Spanish words share this square-related etymology, including 'cuadrado' (square), 'cuadro' (picture frame, painting), and 'cuadra' (city block). All these words preserve the basic concept of something square or rectangular in shape.

English speakers can connect 'escuadra' with several familiar words that come from the same Latin root 'quadrare', such as 'square', 'quadrant', 'quadrilateral', and 'quad'. All these words maintain the connection to the concept of four sides or right angles. The English word 'squad' is also related, as it originally referred to a square formation of soldiers.