1. The persistent keeping within the body of matters normally excreted.

2. In cavity preparation, the prevention of displacement of a restoration.

3. <dentistry> The period during which the patient is wearing an appliance to maintain and stabilise the teeth in the position into which they were moved.

4. <psychology> The persistence to perform a learned behaviour (facts or experiences) after an interval has elapsed in which there has been no performance or practice of the behaviour.

Origin: L. Retentio, from retentare = to hold firmly back

(11 Mar 2008)