What does complementarily mean?
Complementarily is a formal English adverb meaning 'in a complementary manner' — that is, in such a way that two or more distinct things combine to form a complete whole or mutually enhance one another's strengths. Where one thing complements another, each supplies precisely what the other lacks, and acting complementarily captures this relationship in action. The word appears most often in academic and technical prose: in physics, where Niels Bohr's principle of complementarity holds that phenomena like light can be described both as waves and as particles; in systems theory and economics, where components or goods work together productively; and in discussions of design, teamwork, and skill sets, where contrasting abilities fit together effectively. It is derived from 'complement,' ultimately from Latin 'complementum' ('that which fills up'), via the adjective 'complementary.' Because it is rare even in formal writing, speakers more commonly reach for the adjective 'complementary' — but when precision demands an adverb, 'complementarily' fills exactly that role, completing the word's own grammatical set much as its referents complete each other.
adverbIn a way that complements; so as to combine with something else to form a complete whole or to enhance each other's qualities.
- In a way that combines with something else so that each supplies what the other lacks, forming a complete or enhanced whole.
"The two designers worked complementarily, her bold colors balancing his minimalist lines."
"The two approaches complementarily cover each other's blind spots, producing a far stronger analysis than either could alone."
"In the orchestra, the woodwinds and strings function complementarily, filling out the tonal spectrum between them."
It's the rare adverb hiding inside a very common mix-up — 'complementary' pairs things that complete each other, 'complimentary' just says nice things about them.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of complementarily
'Complementarily' derives from the Latin 'complementum', meaning 'that which fills up or completes' (from 'complere', to fill up), which entered English as 'complement' in the 14th century. The adjective 'complementary' developed from it, and the adverb was formed by adding the standard '-ly' ending. Cognates and relatives include 'complete', 'completion', and 'supplement', all tracing back to the same Latin root 'complere'.
Related word forms
How complementarily is actually used
A rare, formal word used chiefly in academic, scientific, and technical writing — particularly in fields like physics (e.g., Bohr's principle of complementarity), systems theory, and design — where the interaction of distinct elements is being described. In everyday speech, people almost always express the idea with the adjective 'complementary' rather than this adverbial form.
Easily confused with complementarily
'Complimentary' means expressing praise or given free of charge, while 'complementarily' means in a manner that completes or enhances something else.