What is Letter Carrier?

Legal Definition
A person employed to carry letters from the post office to the persons to whom they are addressed.

2. The act of congress of March 3, 1851, Statutes at Large of U. S. by Minot, 591, directs, §10, That it shall be in the power of the postmaster general, at all post offices where the postmaster's are appointed by the president of the United States, to establish post routes within the cities or towns, to provide for conveying letters to the post office by establishing suitable and convenient places of deposit, and by employing carriers to receive and deposit them in the post office; and at all such offices it shall be in his power to cause letters to be delivered by suitable carriers, to be appointed by him for that purpose, for which not exceeding one or two cents shall be charged, to be paid by the person receiving or sending the same, and all sums so received shall be paid into the post office department: Provided, The amount of compensation allowed by the postmaster general to carriers shall in no case exceed the amount paid into the treasury by each town or city under the provisions of this section.

3. It is further enacted by c. xxi. s. 2, That the postmaster general shall be, and he is hereby, authorized to appoint letter carriers for the delivery of letters from any post office in California or Oregon, and to allow the letter carriers who may be appointed at any such post office to demand and receive such sum for all letters, newsapers, or other mailable matter delivered by them, as may be recommended by the postmaster for whose office such letter carrier may be appointed, not exceeding five cents for every letter, two cents for every newspaper, and two cents for every ounce of other mailable matter and the postmaster general shall be, and he is hereby, authorized to empower the special agents of the post office department in California and Oregon to appoint such letter carriers in their districts respectively, and to fix the rates of their compensation within the limits aforesaid, subject to, and until the final action of, the postmaster general thereon. And such appointments may be made, and rates of compensation modified from time to time, as may be deemed expedient and the rates of compensation may be fixed, and graduated in respect to the distance of the place of delivery from the post office for which such carriers are appointed, but the rate of compensation of any such letter carrier shall not be changed after his appointment, except by the order of the postmaster general; and such letter carriers shall be subject to the provisions of the forty-first section of the act entitled "An Act to change the organization of the post office, department, and to provide more effectually for the settlement of the accounts thereof," approved July second, eighteen hundred and thirty-six, except in cases otherwise provided for in this act.
-- Bouviers Law Dictionary
Legal Definition
An employee of the post-office, whose duty it is to carry letters from the post-office to the persons to whom they are addressed.
-- Black's Law Dictionary