資料來源 : Webster's Revised Unabridged Dictionary (1913)

Buttonwood \But"ton*wood`\, n. (Bot.)
   The {Platanus occidentalis}, or American plane tree, a large
   tree, producing rough balls, from which it is named; --
   called also {buttonball tree}, and, in some parts of the
   United States, {sycamore}. The California buttonwood is {P.
   racemosa}.