also: ごこうしょう
noun
Honorific term used in formal letters to refer to the recipient's knowledge or awareness of a matter. Almost always appears as ご高承.
ご高承のとおり、来月より新制度が始まります。
As you are aware, the new system will start next month.
noun
acknowledgement; consent; agreement
Honorific epistolary term for the recipient's acknowledgement, compliance, or consent. Used in formal written correspondence, typically as ご高承.
本件につきまして、ご高承のほどお願い申し上げます。
We kindly request your acknowledgement of this matter.
了承 is a general term for understanding and accepting something, while 高承 is an honorific epistolary form used only toward the recipient.
承知 is a common word for knowing or consenting; 高承 is its formal, honorific counterpart used in letters.
Compound of 高 (honorific prefix) and 承 (to receive, to be informed). The exact historical derivation is uncertain, but it is a conventional honorific epistolary term.