rower vs sculler

rower and sculler both are nouns.

Word	Noun	Adjective	Verb	Adverb
rower	Yes	No	No	No
sculler	Yes	No	No	No

As nouns, sculler is a hyponym of rower; that is, sculler is a word with a more specific, narrower meaning than rower:

rower: someone who rows a boat
sculler: someone who sculls (moves a long oar pivoted on the back of the boat to propel the boat forward)

Other hyponyms of rower include oarswoman, stroke, oarsman.

rower (noun)	sculler (noun)
someone who rows a boat	someone who sculls (moves a long oar pivoted on the back of the boat to propel the boat forward)