The Spanish word 'ano' comes directly from the Latin word 'anus', which originally meant 'ring' or 'circle', referring to its circular anatomical shape. The word maintained its anatomical meaning while simplifying its spelling as it evolved from Latin to Spanish.

While 'ano' is a relatively simple Spanish word itself, there aren't many commonly used Spanish words that share its Latin root 'anus' meaning 'ring'.

The English word 'anus' is a direct borrowing from the same Latin word 'anus'. Both Spanish 'ano' and English 'anus' have preserved the original anatomical meaning from Latin, though English retained the Latin spelling while Spanish simplified it.