I. adjective 1. providing necessary support to the primary activities or operation of an organization, system, etc. • ancillary staff.
2. in addition to something else, but not as important • paragraph 19 was merely ancillary to paragraph 16.
II. noun 1. a person whose work provides necessary support to the primary activities of an organization, system, etc. • the employment of specialist teachers and ancillaries.
2. something which functions in a supplementary or supporting role. • undergraduate courses of three main subjects with related ancillaries.
• the system measures engine power at the flywheel with all ancillaries (fan, standard exhaust, etc.) connected.
– origin mid 17th cent.: from Latin ancillaris, from ancilla ‘maidservant’.