complex quantity vs imaginary number

complex quantity and imaginary number both are nouns.

Word	Noun	Adjective	Verb	Adverb
complex quantity	Yes	No	No	No
imaginary number	Yes	No	No	No

As nouns, complex quantity and imaginary number are synonyms defined as:

complex quantity and imaginary number: (mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1

Other synonyms of complex quantity include complex number, imaginary.

complex quantity (noun)	imaginary number (noun)
(mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1	(mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of -1