Meaning of joinder

join•der

Pronunciation: ( join'dur), [key]
— n.
  1. the act of joining.
    1. the joining of causes of action in a suit.
    2. the joining of parties in a suit.
    3. the acceptance by a party to an action of an issue tendered.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.