biplane

Short definition from Wiktionary

Adjective

1. 1
   Composed of, or relating to, two planes (flat surfaces extending infinitely in all directions).
2. 2
   Having, or consisting of, two superposed planes, aerocurves, etc.

Noun

1. 1
   An airplane that has two main wings, one above the other and supported by struts.

Verb

1. 1
   To fly in a biplane.