Telegraph stamp - An adhesive or imprinted revenue stamp paying the cost of a telegram, usually attached to or forming part of the message form.
Tête-bêche - A condition created in plate production, either accidentally or intentionally, in which the stamp design is inverted in alternate vertical or horizontal rows. This results in pairs of stamps in which one adjacent stamp is upside down in relation to the other.
Thematic collecting - Collecting a specific theme.
Too Late - The handstamp applied to a letter to indicate that it had been posted too late for inclusion in the day's dispatch.
TPO - (Traveling Post Office) - Railway Mail Service - The network of railway lines, Railway Post Offices, and Railway Post Office clerks that were used for transporting and processing mail on board moving trains.
Talisman - A talisman is an object or mark which is believed to contain certain magical properties which would provide good luck for the possessor and possibly offer protection from evil or harm. The word comes from the Arabic word Tilasm. The Muslims used on mail a circle with a tail, the symbol of the postal fairy, and sometimes the magic number 8642 was added inside or besides the circle. Jews and Christians used different talisman marks.