a proceeding permitting a person to enter a lawsuit already in progress; in civil law,
admission of a person not an original party to the suit, to protect a right or interest
allegedly affected by the proceeding. The INTERVENOR may wish to join the plaintiff or the defendant or demand something adverse to both.
A person generally can become an intervenor only by proving he or she has an interest in the subject matter of the original
litigation. The purpose of intervention is to prevent delay and unnecessary duplication of lawsuits;
it may be denied, however, if it interferes excessively with the rights of original parties to conduct the suit on their own terms.
EXAMPLE: The Pope family sues Durable Paperboard Company for using chemicals that contain carcinogens in phone repair
products. Two other companies use the same chemicals and fear that a decision adverse to Durable will result in many lawsuits against
them based on the same claim. The companies therefore seek to intervene in the suit between the family and
Source: Barron's Dictionary of Legal Terms, Steven H. Gifis, 5th Edition; © 2016