noun
Polite, formal term used in written correspondence to refer to the recipient's letter. Very rare in modern Japanese; mostly found in classical or highly formal letters.
貴翰を拝見いたしました。
I have read your letter (very formal, archaic).
Standard polite term for 'letter' in modern Japanese; 貴翰 is an archaic, highly formal equivalent used only in classical letter-writing.
Compound of 貴 (honorific prefix) and 翰 (classical kanji for 'writing brush' or 'letter'). The exact historical derivation is uncertain, but it follows a pattern of honorific letter-writing terms.