The Spanish word 'borrador' (meaning 'eraser') comes from the verb 'borrar' (meaning 'to erase') combined with the agent suffix '-dor'. The verb 'borrar' itself can be traced back to the Latin word 'burra', which meant 'coarse wool'. This etymology makes practical sense, as pieces of wool or cloth were historically used to erase writing, particularly on chalkboards, before modern rubber erasers became common. The agent suffix '-dor' is added to verbs to create nouns that refer to the person or thing that performs the action, similar to how '-er' works in English words like 'teacher' or 'eraser'.

Some related Spanish words that might be easier to remember include the verb 'borrar' (to erase), which is very commonly used in everyday Spanish. You might also encounter 'borrón' (blot or smudge) and 'borroso' (blurry or fuzzy), which all share the same root relating to the idea of erasing or obscuring.

While there aren't direct English cognates from the Latin 'burra', English speakers might find it interesting that 'burr' (as in the rough seed pod or the rough sound in speech) comes from a similar Latin root relating to roughness or coarseness. The word 'bureau' also ultimately comes from the same Latin word 'burra', as it originally referred to a cloth covering for a desk before coming to mean the desk itself and later an office or department.