An ancillary provides necessary support to the operation of an organization. Other uses of the word include:
- Ancillary administration
- Ancillary data
- Ancillary doctrine
- Ancillary jurisdiction
- Ancillary market
- Ancillary relief
- Ancillary revenue
- Ancillary services (electric power)
- Ancillary sciences of history
- Ancillary statistic
- Ancillary weapon
- Ancillaries of the Faith