stamped addressed envelope
noun [ C ] uk/ˌstæmpt əˌdrest ˈen.və.ləʊp/ us/ˌstæmpt əˌdrest ˈɑːn.və.loʊp/ (also sae)
（写有自己姓名和地址、贴有邮票的）回邮信封
an envelope with a stamp and your name and address on it that you send inside another envelope to an organization when you want a reply