noun
received letter; correspondence
Archaic term for a letter one has received; used in classical or formal written contexts. Modern Japanese would normally use 手紙 or 来信.
古い文書には「来簡を拝受いたしました」といった表現が見られる。
In old documents, you can find expressions like 'I have received your letter' using 来簡.
Compound of 来 (rai, 'coming') and 簡 (kan, 'letter, document'). The exact historical derivation is uncertain, but it follows a classical pattern for received correspondence.