Part of speech:
Used or held in reserve
(Grammar) Relating to an auxiliary verb.
For use during emergencies:
Possessing some quality, or having been subject to some operation (as substitution), in the second degree; as, a secondary salt, a secondary amine, etc. Compare primary.
Of, for, or functioning as a standby
Being, or having the nature of, a reserve or reserves
Find another word for supplementary. In this page you can discover 14 synonyms, antonyms, idiomatic expressions, and related words for supplementary, like: completing, backup, increase, supplemental, extra, auxiliary, emergency, secondary, standby, subsidiary and additional.