air-sleeve vs visual signal

air-sleeve and visual signal both are nouns.

Word	Noun	Adjective	Verb	Adverb
air-sleeve	Yes	No	No	No
visual signal	Yes	No	No	No

As nouns, visual signal is a hypernym of air-sleeve; that is, visual signal is a word with a broader meaning than air-sleeve:

air-sleeve: a truncated cloth cone mounted on a mast; used (e.g., at airports) to show the direction of the wind
visual signal: a signal that involves visual communication

air-sleeve (noun)	visual signal (noun)
a truncated cloth cone mounted on a mast; used (e.g., at airports) to show the direction of the wind	a signal that involves visual communication