The Spanish word 'verbena' comes from the Latin word 'verbena', which referred to sacred branches or twigs that were used in religious rituals. This Latin term was itself derived from 'verber', meaning 'whip' or 'rod', likely due to the long, straight nature of these branches. Over time, in Spanish, 'verbena' came to specifically refer to the vervain plant (which was one of these sacred plants used in ancient ceremonies) and also developed the meaning of an evening or night festival, possibly because such celebrations historically incorporated these sacred plants or took place where they grew.

While 'verbena' itself is a relatively common Spanish word, there aren't many simpler or more common Spanish words that share its etymology. The word stands somewhat alone in Spanish, primarily used to refer either to the vervain plant or to evening festivals and celebrations.

English speakers might recognize the word 'vervain', which comes from the same Latin root 'verbena'. Vervain refers to the same plant and shares the ancient connection to sacred and medicinal uses. The word entered English through French, but ultimately traces back to the same Latin source as Spanish 'verbena'.