thumb|upright=1.25|1892 imprinted 1d letter card uprated with 1d and 1/2d postage stamps sent from London to Germany, complete with selvages right|thumb|1943 use of an early aerogramme inscribed Air Mail Letter Card. The adhesive stamp, rather than a prepaid [[imprinted stamp or indicium, means that it is not postal stationery but instead a formular air letter card.]]
thumb|upright=1.25|1892 imprinted 1d letter card uprated with 1d and 1/2d postage stamps sent from London to Germany, complete with selvages right|thumb|1943 use of an early aerogramme inscribed Air Mail Letter Card. The adhesive stamp, rather than a prepaid [[imprinted stamp or indicium, means that it is not postal stationery but instead a formular air letter card.]]
In philately, a lettercard or letter card is a postal stationery item consisting of a folded card with a prepaid imprinted stamp. The message is written on the inside and the card is then folded and sealed around the edges. The recipient tears off and discards the perforated selvages to open the card. The fact that it is folded in half before it is sent means there is twice as much space for the message compared with a postal card of the same final size.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).