ancillary /an-silˈə-ri or anˈsi-lə-ri/

1. Auxiliary
2. Supplementary
3. Subsidiary
4. Subordinate
5. (of computer equipment) additional in any way, not a necessary part of the computing process
6. Subserving
7. Ministering

An ancillary thing

• rooftop
• rooftops
• rooftree
• rooftrees
• roofy
• rooibos tea
• rooikat
• rooikats
• rooinek
• rooineks
• rook
• rooked
• rookeries
• rookery
• rookie
• rookier
• rookies
• rookiest
• rooking
• rookish
• rooks
• rooky
• room
• room-divider
• room-dividers