gallows-tree vs gallows

gallows-tree and gallows both are nouns.

Word	Noun	Adjective	Verb	Adverb
gallows-tree	Yes	No	No	No
gallows	Yes	No	No	No

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

gallows-tree: alternative terms for gallows
gallows: an instrument of execution consisting of a wooden frame from which a condemned person is executed by hanging

gallows-tree (noun)	gallows (noun)
alternative terms for gallows	an instrument of execution consisting of a wooden frame from which a condemned person is executed by hanging