coconut tree vs palm tree

coconut tree and palm tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
coconut tree	Yes	No	No	No
palm tree	Yes	No	No	No

As nouns, palm tree is a hypernym of coconut tree; that is, palm tree is a word with a broader meaning than coconut tree:

coconut tree: tall palm tree bearing coconuts as fruits; widely planted throughout the tropics
palm tree: any plant of the family Palmae having an unbranched trunk crowned by large pinnate or palmate leaves

Other hypernyms of coconut tree include palm.

coconut tree (noun)	palm tree (noun)
tall palm tree bearing coconuts as fruits; widely planted throughout the tropics	any plant of the family Palmae having an unbranched trunk crowned by large pinnate or palmate leaves