Lewis Short
(adjective) : conceptīvus, a, um, concipio. *
* That is conceived: fides et dilectio non substantiva animae sed conceptiva,Tert. Res Carn. 40.
* That is ordered, directed; so only feriae, in the Roman ritual, those festivals that were not fixed for a certain day, but were celebrated annually on days appointed by the priests or magistrates, movable festivals. Such were the Compitalia, Paganalia, Sementivae, Latinae, etc., Varr. L. L. 6, § 26; Macr. S. 1, 16; cf. Paul. ex Fest. p. 62, 15 Müll.
Charlton T. Lewis, Charles Short, A Latin Dictionary