• words or propositions so related that each is the negation of the other; "`male' and `female' are complementary terms"
• complementary color: either one of two chromatic colors that when mixed together give white (in the case of lights) or grey (in the case of pigments); "yellow and blue are complementaries"
• complemental: acting as or providing a complement (something that completes the whole)

Equality of rights; natural justice or right; the giving, or desiring to give, to each man his due, according to reason, and the law of God to man; fairness in determination of conflicting claims; impartiality., An equitable claim; an equity of redemption; as, an equity to a settlement, or wife's equity, etc., A system of jurisprudence, supplemental to law, properly so called, and complemental of it.

BMW series are the type of sedans that they have.

1 series, 3 series, 4 series, 5 series, 7series

The plural for series and the singular for series are the same - simply "series."

Inspiron is a series of Dell Laptops. There are the Inspiron series, the XPS series, the Alienware series, and the Z series.