Yosef Mesas (1892–1974), a renowned Jewish Rabbi, claimed that the origin of his surname is the ancient city Mesas near Madrid, named for a medicinal herb common there. He assumes that "Mesas" became a common name in Morocco after the Jews were exiled from Spain in 1492. Mesas suggests that the herb is "Masasa" in Moroccan Arabic (Darija dialect). In the 12th century, Maimonides stated that Moroccans call the genus Plantago "Masasa". This fact refutes Mesas' assumption that the name was brought to Morocco after the Alhambra Decree.

"Mesas" apparently originates from the Spanish term "mesa", meaning "tableland" or "plateau". It can be estimated that the family originated from "Mesas de Ibor", in the Cáceres region of western Spain. It is quite possible that after the family arrived in Morocco the surname became associated with the local "masasa" plant, connecting it with the Spanish city of Mesas.