noun
head of household; householder
Official term for the person registered as the head of a household, especially in the resident register (住民基本台帳). Often used in administrative contexts.
See also: 住民基本台帳
住民票には世帯主の名前が記載されている。
The name of the head of household is recorded on the resident register.
世帯主が変わったので、市
Since the head of household changed, I notified the city office.
家主 means 'landlord' or 'owner of a house', whereas 世帯主 is the registered head of a household, regardless of ownership.
Compound of 世帯 (household) and 主 (master, head). The reading せたいぬし follows the kun'yomi of 主.