English

complementary

From complement + -ary.

Formed from complement + -ary

Proto-Indo-European *pleh₁- ‘to fill’

…

Latin pleō ‘Combining form used to form prefixed verbs…’

Latin compleō ‘to fill up’

Latin complēmentum ‘that which fills up or completes’

Middle English complement

Today it means

adj Acting as a complement; making up a whole with something else.

Language periods are conventional ranges, not dates for this word.

Etymograph / complementary