gaol vs holding cell

gaol and holding cell both are nouns.

Word	Noun	Adjective	Verb	Adverb
gaol	Yes	No	Yes	No
holding cell	Yes	No	No	No

As nouns, holding cell is a hyponym of gaol; that is, holding cell is a word with a more specific, narrower meaning than gaol:

gaol: a correctional institution used to detain persons who are in the lawful custody of the government (either accused persons awaiting trial or convicted persons serving a sentence)
holding cell: a jail in a courthouse where accused persons can be confined during a trial

Other hyponyms of gaol include bastille, hoosegow, hoosgow, house of correction, lockup, workhouse.

gaol (noun)	holding cell (noun)
a correctional institution used to detain persons who are in the lawful custody of the government (either accused persons awaiting trial or convicted persons serving a sentence)	a jail in a courthouse where accused persons can be confined during a trial

gaol (verb)	holding cell (verb)
lock up or confine, in or as in a jail