1) An accessory 2) Auxiliary or adjunct 
Latin, meaning: maidservant, also used by nuns to decribe themselves. 
[gastropod] Ancilla, common name the ancillas, is a genus of sea snails, marine gastropod mollusks in the family Olividae. Species within the genus Ancilla include: ...[quantum computing] An ancilla bit is in general an extra, auxiliary bit which has a secondary role in a logic circuit. In reversible quantum computing circuits, an ancilla bit is a prepared fixed qubit state used for input to a gate to give the gate a more specific logic function (i.e. CNOT to NOT, Toffoli to NOT). ...
Ancilla is a cultivated variety of potato.
an accessory; auxiliary or adjunct. · a maidservant.
maidservant, also used by nuns to describe themselves.