What is Ward?

Legal Definition
In law, a ward is someone placed under the protection of a legal guardian. A court may take responsibility for the legal protection of an individual, usually either a child or incapacitated person, in which case the ward is known as a ward of the court or a ward of the state.

In Australia, New Zealand and the United States, the child is termed a ward of the court. In Ireland and the United Kingdom "the" is not used; the ward is thus termed a ward of court. In Canada the legal term is Crown ward.

Children who are in the custody of government departments, also known as foster care, become wards of the respective government entity, and in the US wards of the states in which they reside. The government or state is in loco parentis to the child, which generally entails assuming all lawful authority to make medical and legal decisions on the child's behalf.
-- Wikipedia
Legal Definition
Courts may appoint guardians to care for people who cannot properly take care of themselves, due to age or legal incompetence. These protected people are the wards of their guardians.
Legal Definition
Domestic relations. An infant placed by authority of law under the care of a guardian.

2. While under the care of a guardian a ward can make no contract whatever binding upon him, except for necessaries. When the relation of guardian and ward ceases, the latter is entitled to have an account of the administration of his estate from the former. During the existence of this relation, the ward is under the subjection of his guardian, who stands in locoparentis.
-- Bouviers Law Dictionary
Legal Definition
A district. Most cities are divided for various purposes into districts, each of which is called a ward.
-- Bouviers Law Dictionary
Legal Definition
Police. To watch in the day time, for the purpose of preventing violations of the law.

2. It is the duty of all police officers and constables to keep ward in their respective districts.
-- Bouviers Law Dictionary
Legal Definition
1. Guarding; care; charge; as, the ward of a castle; so in the phrase "watch and ward."

2. A division in the city of London committed to the special ward (guardianship) of an alderman.

3. A territorial division is adopted in most American cities by which the municipality is separated into a number of precincts or districts called "wards" for purposes of police, sanitary regulations, prevention of fires, elections, etc.

4. A corridor, room, or other division Of a prison, hospital, or asylum.

5. An infant placed by authority of law under the care of a guardian. The person over whom or over whose property a guardian is appointed is called his "ward." Civ. Code Cal. ยง 237.

-Ward-corn. In old English law. The duty of keeping watch and ward, with a horn to blow upon any occasion of surprise. 1 Mon. Ang. 976.
-- Black's Law Dictionary
Legal Definition
One over whom or over whose property a guardian is appointed; a municipal district; in English cities, a municipal district under the supervision of an aider-man; the service of guarding a castle.
-- Ballentine's Law Dictionary