al ‧ ti ‧ tude /ˈæltətjuːd, ˈæltɪtjuːd $ -tuːd/ BrE AmE noun
[ Date: 1300-1400 ; Language: Latin ; Origin: altitudo , from altus 'high, deep' ]
[countable] the height of an object or place above the sea
altitude of
We’re flying at an altitude of 40,000 feet.
high/low altitudes
At high altitudes it is difficult to get enough oxygen.