The Spanish word 'esfuerzo' (meaning 'effort') has its roots in Latin. It begins with the Latin word 'fortis' meaning 'strong', which formed the neuter plural 'fortia' meaning 'strength'. This developed into the Late Latin verb 'fortiare' meaning 'to force'. When this came into Spanish, it was combined with the Latin prefix 'ex-' (meaning 'out') to form the verb 'esforzar' meaning 'to exert effort'. Finally, the action noun suffix '-o' was added to create 'esfuerzo', literally meaning the act of exerting strength or force outward.

The Spanish verb 'esforzar' (to make an effort) is directly related to 'esfuerzo', as 'esfuerzo' is the noun form derived from this verb. You might also encounter 'fuerte' (strong), which comes from the same Latin root 'fortis'. When you're learning these words, you can think about how they all relate to strength and force: 'fuerte' is strong, 'esforzar' is to apply that strength, and 'esfuerzo' is the effort or force being applied.

Several English words share the same Latin ancestry as 'esfuerzo'. The most obvious ones are 'force' and 'fort', both from Latin 'fortis'. 'Fortify', 'fortress', and 'forte' (meaning one's strong point) are also related. The connection becomes clear when you think about how all these words relate to strength: a fort is a strong building, to fortify is to make something stronger, and force is strength applied to accomplish something, just like 'esfuerzo'.