Under the Gaelic system of tanistry, the word (plural , ) had been used for the heir of the chief () or king (). The word was adopted in the 1937 Constitution of Ireland as the title for a member of the government nominated by the Taoiseach to act in their place as needed during periods of the Taoiseach's temporary absence. Tánaiste is the official title of the deputy head of government in both English and Irish, and is not used for other countries' deputy prime ministers (who are referred to in Irish by the generic term , ). The longer Irish form, , is sometimes used in English instead of "the Tánaiste".