Original: An officer of arms is a person appointed by a sovereign or state with authority to perform one or more of the following functions: to control and initiate armorial matters to arrange and participate in ceremonies of state to conserve and interpret heraldic and genealogical records.
Simplified: An officer of arms is someone who is chosen by a sovereign or state to do some important jobs relating to: heraldry and coats of arms arranging and conducting ceremonies of state keeping and interpreting heraldic and genealogical records.