noun.
A person or group of persons, usually armed, responsible for the safety of one or more other persons.
The Century Dictionary and Cyclopedia
noun.
One who protects or defends the person; a life-guard; collectively, the guard charged with the protection of some person, as a prince or an officer; hence, retinue; attendance; following.
the GNU version of the Collaborative International Dictionary of English
noun.
A guard or group of guards to protect or defend the person; a lifeguard.