Sub‐sid″i‐a‐ry (?), a. [L. subsidiarius: cf. F. subsidiaire. See Subsidy.] 1. Furnishing aid; assisting; auxiliary; helping; tributary; especially, aiding in an inferior position or capacity; as, a subsidiary stream.
Chief ruler and principal head everywhere, not suffragant and subsidiary. Florio.
They constituted a useful subsidiary testimony of another state of existence. Coleridge.
2. Of or pertaining to a subsidy; constituting a subsidy; being a part of, or of the nature of, a subsidy; as, subsidiary payments to an ally.
George the Second relied on his subsidiary treaties. Ld. Mahon.