\Join"der\, n. [F. joindre. See {Join}, v. t.] 1. The act of joining; a putting together; conjunction. Confirmed by mutual joinder of your hands. --Shak. 2. (Law) (a) A joining of parties as plaintiffs or defendants in a suit. (b) Acceptance of an issue tendered in law or fact. (c) A joining of causes of action or defense in civil suits or criminal prosecutions.