biplane
n.
airplane with two full wings, one above the other, 1874, as a theoretical notion; first attested 1908 in reference to the real thing; from bi- + plane, n.1. So called from the two "planes" of the double wings.
〔李〕[bi-=having two 有二个…的；plane n.飞机⇒“a plane having two sets of wings 有两副机翼的飞机”→] n. an aircraft with two sets of wings，one above the other 双翼飞机