complex quantity vs imaginary part of a complex number

complex quantity and imaginary part of a complex number both are nouns.

Word	Noun	Adjective	Verb	Adverb
complex quantity	Yes	No	No	No
imaginary part of a complex number	Yes	No	No	No

complex quantity (noun)	imaginary part of a complex 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	the part of a complex number that has the square root of -1 as a factor