wind sock vs visual signal

wind sock and visual signal both are nouns.

Word	Noun	Adjective	Verb	Adverb
wind sock	Yes	No	No	No
visual signal	Yes	No	No	No

As nouns, visual signal is a hypernym of wind sock; that is, visual signal is a word with a broader meaning than wind sock:

wind sock: 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

wind sock (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