Swengel Divorce & Family Law Lawyer, Pennsylvania

A person who initiates a lawsuit. A synonym for plaintiff, used almost universally in some states and in others for certain types of lawsuits, most commonly divorce and other family law cases.

A court procedure that dissolves a marriage and treats it as if it never happened. Annulments are rare since the advent of no-fault divorce but may be obtained in most states for one of the following reasons: misrepresentation, concealment (for example, of an addiction or criminal record), misunderstanding and refusal to consummate the marriage.

A divorce automatically granted by a court when the spouse who is served with a summons and complaint for divorce fails to file a formal response with the court. Many divorces proceed this way when the spouses have worked everything out and there's no reason for both to go to court -- and pay the court costs.

A legal relationship created by a court between a guardian and his ward--either a minor child or an incapacitated adult. The guardian has a legal right and duty to care for the ward. This may involve making personal decisions on his or her behalf, managing property or both. Guardianships of incapacitated adults are more typically called conservatorships .

Consensual sexual relations by a married person with someone other than his or her spouse. In many states, adultery is technically a crime, though people are rarely prosecuted for it. In states that have retained fault grounds for divorce, adultery is always sufficient grounds for a divorce. In addition, some states alter the distribution of property between divorcing spouses in cases of adultery, giving less to the 'cheating' spouse.

A person, not necessarily a lawyer, who is appointed by a court to represent and protect the interests of a child or an incapacitated adult during a lawsuit. For example, a guardian ad litem (GAL) may be appointed to represent the interests of a child whose parents are locked in a contentious battle for custody, or to protect a child's interests in a lawsuit where there are allegations of child abuse. The GAL may conduct interviews and investigations, make reports to the court and participate in court hearings or mediation sessions. Sometimes called court-appointed special advocates (CASAs).

The legal authority to make decisions affecting a child's interests (legal custody) and the responsibility of taking care of the child (physical custody). When parents separate or divorce, one of the hardest decisions they have to make is which parent will have custody. The most common arrangement is for one parent to have custody (both physical and legal) while the other parent has a right of visitation. But it is not uncommon for the parents to share legal custody, even though one parent has physical custody. The most uncommon arrangement is for the parents to share both legal and physical custody.

The biological father of a child born to an unmarried couple who has been established as the father either by his admission or by an agreement between him and the child's mother. An acknowledged father must pay child support.