symbol vs white feather

symbol and white feather both are nouns.

Word	Noun	Adjective	Verb	Adverb
symbol	Yes	No	No	No
white feather	Yes	No	No	No

As nouns, white feather is a hyponym of symbol; that is, white feather is a word with a more specific, narrower meaning than symbol:

symbol: something visible that by association or convention represents something else that is invisible
white feather: a symbol of cowardice

Other hyponyms of symbol include crossbones, cornucopia, horn of plenty, death's head, oriflamme, allegory, emblem.

symbol (noun)	white feather (noun)
something visible that by association or convention represents something else that is invisible	a symbol of cowardice
an arbitrary sign (written or printed) that has acquired a conventional significance