noun
Honorific term used to refer respectfully to another person's son. Often used in formal or polite contexts. The base word is 令息.
See also: 令息
ご令息は今年大学を卒業されたそうですね。
I hear your son graduated from university this year.
社長のご令息が会社を継がれることになった。
The company president's son is to succeed him in the business.
Combination of the honorific prefix ご and 令息 (son), where 令 is a respectful prefix and 息 means 'child' or 'son'. The exact historical derivation is uncertain, but the term is used in modern formal Japanese.