The Spanish verb 'decorar' (to decorate) comes from the Latin verb 'decorare', meaning 'to decorate' or 'to adorn'. This Latin verb was derived from the noun 'decus', which meant 'ornament' or 'dignity'. The evolution from Latin to Spanish maintained both the form and meaning quite closely, with just the typical Spanish infinitive ending '-ar' replacing the Latin '-are'.

Some related Spanish words include 'decoración' (decoration), 'decorativo' (decorative), and 'decoro' (decorum, propriety). All these words share the same Latin root 'decus' and maintain connections to the ideas of adorning, beautifying, or maintaining dignity.

English speakers can easily connect 'decorar' to several familiar English words like 'decorate', 'decoration', and 'decorum'. These English words also derive from the same Latin roots. While 'decorate' shares the same meaning as 'decorar', 'decorum' has maintained more of the 'dignity' aspect of the original Latin 'decus', referring to proper behavior or etiquette.