noun
A formal, honorific term used to refer respectfully to someone else's mother. Not used for one's own mother.
ご母堂様のご逝去を悼み、謹んでお悔やみ申し上げます。
I mourn the passing of your mother and offer my deepest condolences.
先日、山田氏の母堂にお目にかかりました。
The other day, I had the honor of meeting Mr. Yamada's mother.
Compound of 母 (mother) and 堂 (hall, temple), likely derived from the respectful association of a mother with a dignified place. The exact historical derivation is uncertain.