Learner's definition of COMPLEMENTARY
[more complementary; most complementary]
1 : completing something else or making it better : serving as a complement 2 — used of two things when each adds something to the other or helps to make the other better
The print and online publications are complementary, not competitive.
The company owes its success to the complementary talents of its co-owners.
3 : going together well : working well together
◊ Do not confuse complementary with complimentary.