Definition from Nolo’s Plain-English Law Dictionary
1) The personal attendance in court of a party or attorney for the sole purpose of arguing that the court does not have personal jurisdiction over that party. If the party or attorney instead makes a "general" appearance in court, that party is presumed to have waived the right to contest the court's jurisdiction. 2) A one-time court appearance by an attorney for a party who either is represented by another attorney or is not represented at the time. Quite often an attorney will make a "special appearance" to protect the interests of a potential client, but before a fee has been paid or arranged.