(present) head of a family
当主が遺産を相続した。
The head of the family inherited the estate.
旧家の当主は重い責任を担っている。
As head of an old house, he bears heavy responsibility.
老舗の当主が急逝し、番頭が暫定的に経営を引き継いだ。
When the head of the long-established shop died suddenly, the chief clerk took over the business for the time being.