The Spanish verb 'mezclar' (meaning 'to mix') traces its origins back to the Classical Latin word 'miscere', which also meant 'to mix'. This evolved into the Vulgar Latin form 'misculare', maintaining the same meaning. As the language developed into Old Spanish, the word became 'mesclar', and finally evolved into the modern Spanish 'mezclar'. The transformation from 'miscere' to 'mezclar' shows typical sound changes in Spanish evolution, including the development of the 'zc' consonant cluster from the earlier 's' sound.

A common related Spanish word is 'mezclado' (mixed), which is the past participle of 'mezclar'. Another related term is 'mezcla' (mixture), the noun form of the verb. The word 'mestizo', referring to a person of mixed ancestry, also shares the same Latin root, though it developed through a different path from the same concept of mixing.

English speakers might recognize the connection to several English words that come from the same Latin root 'miscere'. These include 'mix' itself, as well as 'miscellaneous' (various mixed things), 'medley' (a mixture), and 'miscible' (capable of being mixed). The word 'medley' came through Old French 'medlee', which was related to the same Vulgar Latin root as 'mezclar'.