The height of something above sea level or the ground. It is often used when talking about mountains, airplanes, or weather.
From Latin *altitūdō*, meaning “height, depth,” from *altus* (“high, deep”). It entered English through Middle French in scientific and navigational contexts.
The Latin root *altus* means both “high” and “deep,” so the same word originally covered up and down. That’s why “altitude” feels natural for mountains and airplanes, even though the root once included the idea of depth, too. Language didn’t always care which direction you went—just how far.
Complete word intelligence in one call. Free tier — 50 lookups/day.