Smithsonian paleontologist Gilmore originally described the holotype, USNM 10486, a left scapula (shoulder bone), and the paratype USNM 10487, a right ischium (pelvic bone) in 1922, naming the type species "Alamosaurus sanjuanensis". Contrary to popular assertions, the dinosaur is not named after the Alamo in San Antonio, Texas, or the battle that was fought there. The holotype, the specimen the name was based on, was discovered in New Mexico and, at the time of its naming, "Alamosaurus" had not yet been found in Texas. Instead, the name "Alamosaurus" comes from Ojo Alamo, the geologic formation in which it was found and which was, in turn, named after the nearby Ojo Alamo trading post (since this time there has been some debate as to whether to reclassify the "Alamosaurus"-bearing rocks as belonging to the Kirtland Formation or whether they should remain in the Ojo Alamo Formation). The term "alamo" itself is a Spanish word meaning "poplar" and is used for the local subspecies of cottonwood tree. The term "saurus" is derived from "saura" (σαυρα), Greek for "lizard" and is the most common suffix used in dinosaur names. There is only one species in the genus, "Alamosaurus sanjuanensis", which is named after San Juan County, New Mexico, where the first remains were found.