'algarrobo' originates from Spanish, specifically the word 'algarrobo,' which comes from Andalusi Arabic 'al-karrūb' (الخرّوب), where 'al-' meant 'the' and 'karrūb' referred to the carob (the tree or its pods).

'algarrobo' entered Spanish from Andalusi Arabic 'al-karrūb' (and Classical Arabic 'karrūb'), itself related to Late Latin 'carōba' and Greek 'κέρατον' / 'kératon' (terms for the carob or pod); through these stages the form developed into modern Spanish 'algarrobo' and was later applied in the Americas to some native hardwoods.

Initially it referred specifically to the Mediterranean carob tree and its pods; over time, especially after Spanish colonization of the Americas, the term was extended to include various similar hardwood trees (e.g., Prosopis species) and their wood.