Myrtillocactus myr·til·lo·cactus uncommon noun 1. small genus of arborescent cacti of Mexico and Central America Synonymsgenus Myrtillocactus Related words Word family Myrtillocactus geometrizans Broader terms caryophylloid dicot genus Parts Cactaceae Part of garambulla WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.