The Spanish word 'cuarta' comes from the Latin word 'quartus' meaning 'fourth'. The Latin 'quartus' evolved into the Spanish masculine form 'cuarto', and then the feminine suffix '-a' was added to create 'cuarta', meaning 'fourth' when referring to feminine nouns.

Some common related Spanish words include 'cuarto' (meaning 'fourth' or 'quarter', and also 'room'), 'cuarteto' (quartet), and 'cuartel' (barracks, originally meaning a quarter of a town). All these words share the basic concept of 'four' or 'fourth' in their meanings.

English speakers might recognize the connection to words like 'quarter', 'quart', and 'quartet', which all come from the same Latin root 'quartus'. Just as 'cuarta' means 'fourth' in Spanish, these English words all relate to the concept of four or a fourth part of something. For example, a quarter is one-fourth of a whole, a quart is one-fourth of a gallon, and a quartet is a group of four.