The Spanish verb 'usar' (to use) comes from Latin 'usus' meaning 'use', which itself derives from the Latin verb 'uti' meaning 'to use'. The modern Spanish form was created by adding the common Spanish infinitive suffix '-ar' to the Latin base 'us-'.

Some common related Spanish words include 'uso' (noun meaning 'use'), 'usual' (usual, common), and 'usuario' (user). All these words share the same Latin root and maintain meanings closely connected to the concept of 'using' or 'use'.

English speakers can connect 'usar' to many familiar English words that come from the same Latin source, such as 'use', 'usual', 'utility', 'utensil', and 'utilize'. The connection is easy to see both in form (they all contain 'us-' or 'ut-') and meaning (they all relate to the concept of using or being useful).