a. Having two surfaces; -- said specif. of aëroplane wings or aërocurves which are covered on both sides with fabric, etc., thus completely inclosing their frames. [ Webster 1913 Suppl. ]
adj. paved; -- of roads. Opposite of
a. Having one surface; -- said specif. of aeroplanes or aerocurves that are covered with fabric, etc., on only one side. [ Webster 1913 Suppl. ]