Subsidiary
WordNet
adjective
(1) Functioning in a subsidiary or supporting capacity
"The main library and its auxiliary branches"
(2) Furnishing added support
"An ancillary pump"
"An adjuvant discipline to forms of mysticism"
"The mind and emotions are auxiliary to each other"
(3) Of or relating to or being a subsidy
noun
(4) A company that is completely controlled by another company
(5) An assistant subject to the authority or control of another