The Spanish verb 'estimular' (to stimulate) comes from the Latin verb 'stimulare' meaning 'to goad or incite.' This Latin verb was derived from the noun 'stimulus,' which literally meant 'goad' or 'spur' - a pointed rod or stick used to prod animals forward. Over time, the meaning evolved from the physical act of prodding to the more general sense of encouraging or inciting action, which is reflected in the modern Spanish meaning.

A closely related Spanish word is 'estímulo' (stimulus, incentive), which is a direct descendant of the Latin 'stimulus.' You might also encounter 'estimulante' (stimulating, stimulant), which is the present participle form of 'estimular.'

The English words 'stimulate,' 'stimulus,' and 'stimulant' are perfect cognates with their Spanish counterparts, as they come from the same Latin roots. The similarity in both spelling and meaning makes these words easy to remember. Just as in Spanish, these English words have evolved from the concrete meaning of physically prodding something to the more abstract sense of encouraging activity or response.