n.

1. 高，高度；海拔[S1]
   The plane was then flying at an altitude of 8000 feet.

   当时飞机在八千英尺的高度飞行。

2. 高处，高地[P1]
   He found it difficult to breathe at high altitudes.

   他觉得在高空呼吸困难。

3. 【数】顶垂线，高线[C]
4. （指等级，地位等）高级[C]

n.