1. An instrument that automatically records changes in altitude, typically used in aircraft or meteorology.
Usage: technical; also called an altimeter when used to measure altitude directly

Examples

• The pilot checked the altigraph to monitor the aircraft's climbing rate.
• The weather station's altigraph provided continuous data on atmospheric pressure changes.
• Modern aircraft rely on digital altigraphs rather than mechanical ones.
• The altigraph recorded the mountain climber's elevation throughout the expedition.