holding pen vs holding paddock

holding pen and holding paddock both are nouns.

Word	Noun	Adjective	Verb	Adverb
holding pen	Yes	No	No	No
holding paddock	Yes	No	No	No

As nouns, holding pen and holding paddock are synonyms defined as:

holding pen and holding paddock: a pen where livestock is temporarily confined

Other synonyms of holding pen include holding yard.

holding pen (noun)	holding paddock (noun)
a pen where livestock is temporarily confined	a pen where livestock is temporarily confined