The Spanish verb 'medir' (to measure) comes from the Latin verb 'metiri', which also meant 'to measure'. This Latin word developed alongside the Ancient Greek word 'μέτρον' (metron), meaning 'measure'. As Latin evolved into Spanish, 'metiri' underwent phonetic changes, with the '-tiri' ending shifting to '-dir', giving us the modern Spanish 'medir'.

Several common Spanish words are related to 'medir', including 'medida' (measurement), 'medidor' (meter/measuring device), and 'medio' (half/middle). These words all share the basic concept of measurement or determining size/quantity.

Many English words share the same Greek-Latin roots as 'medir'. Some common examples include 'meter' (both the measuring device and the unit of length), 'metric' (relating to measurement), 'measure', and even 'immense' (literally 'without measure'). The prefix 'metro-' in words like 'metropolis' also comes from this same ancient root. These connections can help English speakers remember that 'medir' relates to measurement.