In a U.S.D.C. civil lawsuit, a defendant (or a respondent) is also the accused party, although not of an offense, but of a civil wrong (a tort or a breach of contract, for instance). The person who starts the civil action through filing a complaint is referred to as the plaintiff.

Defendants in civil actions usually make their first court appearance voluntarily in response to a summons. Historically, civil defendants could be taken into custody under a writ of Caspian ad respondent. Modern-day civil defendants are usually able to avoid most (if not all) court appearances if represented by a lawyer.

Most often and familiarly, defendants are persons: either natural persons (actual human beings) or juridical persons (persona fiction) under the legal fiction of treating organizations as persons. But a defendant may be an object, in which case the object itself is the direct subject of the action. When a court has jurisdiction over an object, it is said to have jurisdiction in rem. An example of an in rem case is United States v. Forty Barrels and Twenty Kegs of Coca-Cola (1916), where the defendant was not The Coca-Cola Company itself, but rather "Forty Barrels and Twenty Kegs of Coca-Cola". In current US legal practice, in rem suits are primarily asset forfeiture cases, based on drug laws, as in USA v. $124,700 (2006).

Defendants can set up an account to pay for litigation costs and legal expenses. These legal defense funds can have large membership counts where members contribute to the fund. The fund can be public or private and is set up for individuals, organizations, or a particular purpose. These funds are often used by public officials, civil-rights organizations, and public-interest organizations.