Altitude

Noun

1. The absolute height of a location, usually measured from sea level.

   "As the altitude increases, the temperature gets lower, so remember to bring warm clothes to the mountains."

2. A vertical distance.
3. The line perpendicularly connecting a figure’s vertex, especially a triangle’s apex, to the side opposite to the vertex.

   "All three altitudes of any triangle will always meet at point known as the orthocentre or orthocenter."

4. The length of such a line; the distance measured perpendicularly from a figure's vertex to the side opposite to the vertex.

   "The perpendicular height of a triangle is known as its altitude."

5. The angular distance of a heavenly body above our Earth's horizon.