“Reboant” is used almost exclusively in a poetic sense. Coming from the Latin verb “reboō,” meaning “to bellow or resound,” this adjective describes sounds that ring and reverberate with majestic volume. Someone wouldn’t use the adjective for a high, shrill note like a bird song. Instead, a reboant sound might be a ship’s horn blowing, a lion roaring, or a bell clanging in a tower.