Jurate Gacionyte altitude al⋅ti⋅tude [al-ti-tood] –noun 1. the height of anything above a given planetary reference plane, esp. above sea level on earth. 2. extent or distance upward; height. 3. Astronomy. the angular distance of a heavenly body above the horizon. 4. Usually, altitudes. a high place or region: mountain altitudes. a home a b c d e f g h i j k l m n o p q r s t u v w x y z altitude ambiance antique anonymous antler apocalyptic alligator alone altered apple-juice arm art as-az