from the GNU version of the Collaborative International Dictionary of English
- n. An airplane with four superposed main supporting surfaces. Contrasted with
triplane biplaneand monoplane. They are now used only for hobbyist or historical activities.
from The Century Dictionary and Cyclopedia
- n. A plane quadrilateral having its opposite or alternate sides equal and one pair of these crossing each other.
- n. A system of four plane links pivoted together so that the pivots are vertexes of a contraparallelogram. It is an extension by Sylvester and Kempe of what Sylvester called the plagiograph or skew-pantograph to Hart's contraparallelogram.
Sorry, no etymologies found.