Meaning of retained object complement

retained' ob'ject com'plement

Pronunciation: [key]
— Gram. Gram.
  1. an object complement that is kept in its predicative position following the verb when the verb is transformed into the passive voice, as genius in He was considered a genius from (They) considered him a genius.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.