[seer-ee-uh
s] 
| 1. | any of various plants of the genus Cereus, of the cactus family, having large, usually white, funnel-shaped flowers. |
| 2. | any of several related, similar plants, esp. of the genera Hylocereus, Nyctocereus, and Selenicereus. |
| ce·re·us (sîr'ē-əs) n. Any of several cacti of the genus Cereus or closely related genera, such as a night-blooming cereus. [New Latin Cēreus, genus name, from Latin cēreus, candle (from its shape), from cēra, wax; see cerate.] |