• Webster's Revised Unabridged Dictionary
    • a Twibilled Armed or provided with a twibil or twibils.
    • ***
Century Dictionary and Cyclopedia
    • twibilled Armed with a twibill or twibills.
    • ***


In literature:

We have 'twilight', but 'twibill' = bipennis (Chapman) is extinct.
"English Past and Present" by Richard Chevenix Trench
The first to make such inclined tubes into a sectional form was Twibill, in 1865.
"Steam, Its Generation and Use" by Babcock & Wilcox Co.