American Heritage Dictionary
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Century Dictionary
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GNU Webster's 1913
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WordNet
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Elsewhere on the web
The giant was in the midst of it; but weak as the bulrush were the mighty limbs of Maximus before the rushing gale.— Ungava
The name bulrush is more correctly applied to Scirpus lacustris_, a member of a different family (Cyperaceae), a common plant in wet places, with tall spongy, usually leafless stems, bearing a tuft of many-flowered spikelets.— Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary"
A man may "bow down his head as a bulrush," or fast, or clothe himself in sackcloth, when he is an utter stranger to that "repentance to salvation not to be repented of."— The Ancient Church Its History, Doctrine, Worship, and Constitution
To droop one's head like a bulrush, And to lie down in sackcloth and ashes?— The Makers and Teachers of Judaism

American Heritage Dictionary (1)
Century Dictionary (1)
Bubble size: how much this word was used in a year
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You can expect to see this word about twice a year.