Section 22. In this section and in sections twenty-three to thirty, inclusive, the following words shall have the following meanings unless a different meaning is clearly required by the context:—

''Licensee'', any person licensed under section twenty-five.

''Private detective business'', the business of private detective or private investigator, and the business of watch, guard or patrol agency.

''Private detective'' or ''private investigator'', a person engaged in business as a private detective or private investigator, including any person who, for hire, fee, reward or other consideration, (1) uses a lie-detector for the purpose of obtaining information with reference to the conduct, integrity, efficiency, loyalty or activities of any person or (2) engages in the business of making investigations for the purpose of obtaining information with reference to any of the following matters, whether or not other functions or services are also performed for hire, fee, reward or other consideration, or other persons are employed to assist in making such investigations:—

(a) Crime or other acts committed or threatened against the laws or government of the United States or any state of the United States;

(b) The identity, habits, conduct, movements, whereabouts, affiliations, associations, transactions, reputation or character of any person;

(c) Libels, fires, losses, accidents, or damage to, or loss or theft of, real or personal property;

(d) Evidence to be used before any investigating committee, board of award, or board of arbitration, or in the trial of civil or criminal cases.

''Watch, guard or patrol agency'', the business of watch, guard or patrol agency, including the furnishing, for hire or reward, of watchmen, guards, private patrolmen or other persons to protect persons or property, to prevent the theft or the unlawful taking of goods, wares or merchandise, or the misappropriation or concealment thereof or of money, bonds, stocks, notes or other valuable documents, papers or articles of value, or to procure the return thereof, whether or not other functions or services are also performed for hire or reward, or other persons are employed to assist therein.