The Spanish word 'calavera' (meaning 'skull') comes from the Latin word 'calvaria', which also meant 'skull'. Going back further, 'calvaria' derives from the Latin adjective 'calvus', meaning 'bald'. This etymology makes intuitive sense since a skull is essentially a 'bald head' - the bare bone structure without hair or flesh.

While 'calavera' itself is a common Spanish word, particularly known for its use in Day of the Dead (Día de los Muertos) celebrations, there aren't many simpler or more common Spanish words that share its etymology. However, you might encounter 'calvo', meaning 'bald', which comes from the same Latin root 'calvus'.

In English, we have the medical term 'calvaria', which refers to the upper part of the skull and comes directly from the same Latin word. While this isn't a common everyday word, medical students might recognize it. The English word 'calvary' (meaning the place where Jesus was crucified) comes from a different Latin root and is not related to 'calavera' despite the similar spelling.