The Spanish word 'perímetro' (meaning 'perimeter') comes from Latin 'perimetros', which was borrowed from Ancient Greek 'perimetros'. The Greek word was formed by combining two elements: 'peri-' meaning 'around' and 'metron' meaning 'measure'. So literally, the word means 'measure around' - which makes perfect sense given that a perimeter is the continuous line forming the boundary of a closed geometric figure.

Several common Spanish words share these same Greek roots. Words with 'peri-' include 'periferia' (periphery) and 'período' (period). Words containing 'metro' include 'metro' (meter), 'métrico' (metric), and 'termómetro' (thermometer). Understanding these connections can help you remember that 'perímetro' relates to measuring around something.

The English cognate 'perimeter' is nearly identical to the Spanish word. Other related English words using 'peri-' include 'peripheral' and 'period'. The '-meter' element appears in many English measurement words like 'meter', 'thermometer', 'speedometer', and 'kilometer'. These connections show how both Spanish and English have preserved these ancient Greek elements for describing measurement and circular motion.