longitude vs angular distance

longitude and angular distance both are nouns.

Word	Noun	Adjective	Verb	Adverb
longitude	Yes	No	No	No
angular distance	Yes	No	No	No

As nouns, angular distance is a hypernym of longitude; that is, angular distance is a word with a broader meaning than longitude:

longitude: the angular distance between a point on any meridian and the prime meridian at Greenwich
angular distance: the angular separation between two objects as perceived by an observer

longitude (noun)	angular distance (noun)
the angular distance between a point on any meridian and the prime meridian at Greenwich	the angular separation between two objects as perceived by an observer