The Spanish word 'desierto' (meaning 'desert') comes from the Latin word 'desertus' meaning 'abandoned' or 'deserted'. The Latin word 'desertus' itself is formed from two parts: the prefix 'de-' meaning 'down' or 'away', and the verb 'serere' meaning 'to join or connect'. When combined, these elements created the concept of something being 'un-joined' or 'disconnected', which evolved to mean 'abandoned' or 'deserted'. Over time, this meaning specialized to refer specifically to barren, uninhabited lands - what we now call deserts.

A closely related Spanish word is 'desertar' (to desert or abandon), which comes from the same Latin root. Another related word is 'deserción' (desertion). These words maintain the original sense of abandonment from the Latin 'desertus'.

The English words 'desert' (both the noun and verb) and 'deserted' are direct cognates of the Spanish 'desierto', all coming from the same Latin source 'desertus'. This makes it easy to remember - a desert is essentially a 'deserted' place! The English word 'desertion' is also related, maintaining the original meaning of abandonment.