Pronunciation: (pu-zish'u-nur), [key]
1. a person or thing that positions.
2. Orthodontics.a removable device of resilient plastic material worn in the mouth usually during sleep to produce minor adjustments in the position of teeth after straightening appliances have been taken off.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.