Definition of buttonball tree in English:

buttonball tree

noun

another term for sycamore (sense 1 of the noun)
‘The house was shaded by a row of buttonball trees which extended far up the street, of which a few aged veterans remain.’
  • ‘Sycamore, also called American planetree, buttonball tree, or buttonwood, is a common shade tree throughout much of the eastern United States.’
  • ‘It happens to belong to the planetree family and sports one-inch thick, spherical fruits supported on long stems leading to the name of buttonball tree.’
  • ‘In our country there are three native species: P. occidentalis, called the sycamore, buttonball tree, or the American plane tree; P. wrightii, the Arizona sycamore; and P. racemosa, the California or western sycamore.’

Pronunciation

buttonball tree

/ˈbətnbôl ˌtrē/ /ˈbətnbɔl ˌtri/