phoneme vs allophone

phoneme and allophone both are nouns.

Word	Noun	Adjective	Verb	Adverb
phoneme	Yes	No	No	No
allophone	Yes	No	No	No

As nouns, allophone is a hyponym of phoneme; that is, allophone is a word with a more specific, narrower meaning than phoneme:

phoneme: (linguistics) one of a small set of speech sounds that are distinguished by the speakers of a particular language
allophone: (linguistics) any of various acoustically different forms of the same phoneme

phoneme (noun)	allophone (noun)
(linguistics) one of a small set of speech sounds that are distinguished by the speakers of a particular language	(linguistics) any of various acoustically different forms of the same phoneme