The Spanish word 'abate' meaning 'abbot' comes from the Italian word 'abate' with the same meaning. The Italian term derives from Late Latin 'abbas', which also meant 'abbot' - the head of a monastery. This is a straightforward borrowing chain where the meaning remained stable as the word passed from Late Latin through Italian into Spanish.

The Spanish word 'abad' (meaning 'abbot') is a close relative of 'abate', as it comes from the same Late Latin root 'abbas'. While 'abate' entered Spanish through Italian, 'abad' developed more directly from Latin. Both words maintain the ecclesiastical meaning referring to the head of a monastery.

English speakers might recognize the connection to the word 'abbot', which shares the same Late Latin ancestor 'abbas'. The English 'abbey' and 'abbess' are also related, all stemming from this ecclesiastical Latin term. While Spanish 'abate' and English 'abbot' have maintained their original meaning referring to the head of a monastery, 'abbey' broadened to refer to the monastery itself.