Meaning

noun tall marsh plant with cylindrical seed heads that explode when mature shedding large quantities of down; its long flat leaves are used for making mats and chair seats; of North America, Europe, Asia a

noun tall rush with soft erect or arching stems found in Eurasia, Australia, New Zealand, and common in North America

originFrom Middle English bulrish, perhaps from bule (“bull”) (in the sense of "large") + rish (“rush”).

Etymology from Wiktionary, CC BY-SA 3.0