also: だいだんな
noun
Honorific term for one's own father-in-law, used when speaking respectfully about him to others. Often used in traditional or formal contexts.
大旦那は今年で七十歳になります。
My father-in-law will be seventy this year.
noun
Honorific term for one's employer or master, especially in traditional or historical contexts such as a merchant house or a master–servant relationship.
大旦那のおかげで商売がうまくいっています。
Thanks to the master, the business is going well.
noun
principal temple supporter; influential parishioner
Refers to a major benefactor or influential supporter of a Buddhist temple. The spelling 大檀那 is sometimes used for this sense.
あの方はこの寺の大旦那として知られています。
That person is known as the principal supporter of this temple.
旦那 is a general term for husband, master, or patron, while 大旦那 adds the honorific prefix 大 and specifically refers to a father-in-law, employer, or major temple supporter in a respectful way.
Compound of 大 (おお, 'great') + 旦那 (だんな, 'master, husband, patron'). The reading おおだんな is the most common; だいだんな is a less frequent alternative.