regression curve vs regression line

regression curve and regression line both are nouns.

Word	Noun	Adjective	Verb	Adverb
regression curve	Yes	No	No	No
regression line	Yes	No	No	No

As nouns, regression curve and regression line are synonyms defined as:

regression curve and regression line: a smooth curve fitted to the set of paired data in regression analysis; for linear regression the curve is a straight line

regression curve (noun)	regression line (noun)
a smooth curve fitted to the set of paired data in regression analysis; for linear regression the curve is a straight line	a smooth curve fitted to the set of paired data in regression analysis; for linear regression the curve is a straight line