paddle wheel vs paddlewheel

paddle wheel and paddlewheel both are nouns.

Word	Noun	Adjective	Verb	Adverb
paddle wheel	Yes	No	No	No
paddlewheel	Yes	No	No	No

As nouns, paddle wheel and paddlewheel are synonyms defined as:

paddle wheel and paddlewheel: a large wheel fitted with paddles and driven by an engine in order to propel a boat

paddle wheel (noun)	paddlewheel (noun)
a large wheel fitted with paddles and driven by an engine in order to propel a boat	a large wheel fitted with paddles and driven by an engine in order to propel a boat