evidence: Cerro de las Mesas [...] Ballista Synonyms or Related Words: Balista Category: Artifact [...] Mesa Category: Geography Deﬁnition: A steep-sided, ﬂat-topped hill, tableland, or mountain. A mesa is an isolated and relatively ﬂat-topped natural elevation usu. more extensive than a butte and less extensive than a plateau. The term is also applied to a broad terrace with an abrupt slope on one side. In US Southwest, mesas were often used for settlements in pre-Columbian times.