1. The persistent keeping within the body of matters normally excreted.
2. In cavity preparation, the prevention of displacement of a restoration.
3. (Science: 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. (Science: 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
The power of retaining and recalling past experience; he had a good memory when he was younger.