Greek machaira ‘dagger’ + Cereus, the name of a genus of columnar cacti and a designation for columnar cacti in general. “The generic name is from the Greek, signifying dagger-cereus, with reference to the dagger-like spines.”
Stenocereus eruca (Machaerocereus eruca). Image credit: Stan Shebs / CC BY-SA 3.0
Maarten H.J. van der Meer (2022 Feb 05). Machaerocereus. Dictionary of Cactus Names. Retrieved from https://www.cactusnames.org/Machaerocereus