Vatu is a word that refers to the currency used in the island nation of Vanuatu. However, there are a few synonyms for the word vatu that can be used in different contexts. For example, ash or cinder can be referred to as vatu in geology. Similarly, rocks or stones can also be called vatou in some cultures. Another interesting synonym for vatu is 'kor' which is used in some parts of Indonesia to refer to traditional houses made from wood and bamboo. Additionally, 'vatu' can be translated to 'stone' or 'rock' in many Pacific Islander languages.