What does "cereus" mean?

Cereus: A genus of plants of the Cactus family. They are natives of America, from California to Chili. Note: Although several species flower in the night, the name Night- blooming cereus is specially applied to the Cereus grandiflorus, which is cultivated for its beautiful, shortlived flowers. The Cereus giganteus, whose columnar trunk is sometimes sixty feet in height, is a striking feature of the scenery of New Mexico, Texas, etc.