A Basque folk etymology says the place name Arantzazu comes from the words "Arantzan zu?", meaning "You, among the thorns?" (I have also seen it translated as "Is that you in the hawthorn?"), supposedly spoken by a 15th-century shepherd who, according to legend, saw an apparition of the Virgin Mary in a thorn bush. However linguists say the place name probably comes from the Basque words for "place abounding in hawthorn". As a personal name it can also be found in the Spanish form Aránzazu.
As a personal name it can also be found in the Spanish form Aránzazu.