Section 735 ILCS 5/2-401 - Designation of parties-Misnomer(a) The party commencing an action shall be called the plaintiff. The adverse party shall be called the defendant.(b) Misnomer of a party is not a ground for dismissal but the name of any party may be corrected at any time, before or after judgment, on motion, upon any terms and proof that the court requires.(c) A party shall set forth in the body of his or her pleading the names of all parties for and against whom relief is sought thereby.(d) Unless a contrary meaning is indicated, wherever used in this Act and in rules adopted pursuant hereto the term "plaintiff" includes counterclaimants and third-party plaintiffs, and the term "defendant" includes third-party defendants and parties against whom relief is sought by counterclaim.(e) Upon application and for good cause shown the parties may appear under fictitious names.