The Spanish word 'tostón' comes from the verb 'tostar' (meaning 'to toast') combined with the augmentative suffix '-ón'. The verb 'tostar' itself derives from Latin 'tostare', meaning 'to dry' or 'to roast'. The augmentative suffix '-ón' adds the sense of something being large or intensified, so 'tostón' literally means something like 'big toasted thing' or 'well-roasted item'.

The most obvious related Spanish word is the common verb 'tostar' (to toast). You might also recognize this in words like 'tostada' (a toasted tortilla) and 'tostadora' (toaster). All these words share the basic meaning of toasting or roasting something.

While not directly related, English speakers might recognize similarity to the word 'toast', which comes from the same Latin root 'tostare'. The English word maintained a similar meaning to the Spanish cognates, referring to bread that has been browned by exposure to heat.