noun
An aircraft with a single pair of wings. Technical term used in aviation contexts.
単葉飛行機は複葉機より空気抵抗が少ない。
A monoplane has less air resistance than a biplane.
複葉機 (biplane) has two sets of wings, while 単葉飛行機 (monoplane) has only one.
Compound of 単葉 (single wing) + 飛行機 (airplane). The term is a direct calque from English 'monoplane'.