Lewis Short
(verb) : ancillor, ātus, 1, and n. ancilla, pr.
* To serve as handmaid; hence, in gen., to serve, to attend upon, to be subservient to, etc. (only ante-class. and post-Aug.): invita ancillans, Att. ap. Non. p. 72, 3: uxoribus ancillantur, Titin. ib.: aestus (maris) ancillantes siderum avido trahenti etc.,Plin. 2, 97, 99, § 213: cetera membra ancillari et subservire capiti,App. Dogm. Plat. 1, p. 9, 17.
Charlton T. Lewis, Charles Short, A Latin Dictionary