ルネットルネットMeanings1nounlunette; lunette window; half-moon windowarchitectureArchitectural term for a semicircular window or wall opening, often above a door or in a vaulted ceiling.from French教きょう会かいの正しょう面めんに美うつくしいルネットがはめ込こまれている。A beautiful lunette is set into the front of the church.