'Atlantosaurus' originates from Greek elements, specifically 'Atlas' (Ἄτλας) and 'sauros' (σαῦρος), where 'Atlas' referred to the mythic Titan (used as a name element) and 'sauros' meant 'lizard'.

'Atlantosaurus' was coined in the late 19th century as a genus name for certain sauropod fossils; later paleontological work transferred many of these remains to other genera (notably 'Apatosaurus') or judged the name insufficiently diagnostic, leaving 'Atlantosaurus' as historically used but taxonomically problematic.

Initially, the name literally meant 'Atlas lizard' as a taxonomic label; over time its use shifted from a practical genus assignment to a historically noted but often dubious or synonymized name in sauropod taxonomy.