noun
whole family; all the members of one's family
Refers to every member of one's own family, often used in contexts like family activities or events.
家内中で旅行に行く。
The whole family goes on a trip.
家内中が集まって夕食を食べた。
All the members of the family gathered and ate dinner.
一家 can refer to a family as a unit or household, but 家内中 focuses on the inclusiveness of all members.
Compound of 家内 (かない, 'inside the house; one's own family') and 中 (じゅう, 'throughout; all').