/ Dictionary / Index P positioner: Meaning and Definition of Find definitions for: po•si•tion•er Pronunciation: (pu-zish'u-nur), [key] — n. a person or thing that positions. 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. See also: positioner (Thesaurus) position effect position isomer Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language