1. Functional interaction between two defective viruses permitting replication under conditions inhibitory to the single virus.
2. Interaction between two genetic units, one or both of which are defective, permitting the organism containing these units to function normally, whereas it could not do so if either unit were absent.
The information shown above for complementation is provided by Stedman's.
* Stedman's, part of Lippincott Williams & Wilkins, provide a comprehensive line of health-science publications for healthcare professionals and medical students.