Lo Celso is a surname characteristic of Sicily, formed by the southern article Lo and the personal name Celso. On this reading, the surname would have a patronymic origin and would originally have meant "the one of Celso" or "descendant of Celso".

According to A. Bongioanni, the name Celso derives from the Latin Celsus, which means "tall", "lofty" or "eminent". Its spread in Italy was favoured by the cult of several saints of this name, especially Saint Celsus, a martyr venerated alongside Saint Nazarius in Milan.

V. Blunda proposes a different reading for the Sicilian sphere. He considers that some surnames of this group derive not from the Latin name Celsus, but from the Sicilian dialect word ceusu, which means "mulberry tree". In that case, the surname would belong to the group of phytonymic surnames, those originating in the names of plants. It could have arisen as a place name applied to someone who lived near a mulberry tree, or as a byname connected with sericulture, an activity very widespread in Sicily during the Middle Ages thanks to the cultivation of mulberry trees for the rearing of silkworms.