Wiktionary
n. The dwelling where a person usually lives. A person may have only one primary residence at any given time and is used for legal purposes such as determining where a person votes or pays taxes.
Wikipedia
A person's primary residence, or main residence is the dwelling where they usually live, typically a house or an apartment. A person can only have one primary residence at any given time, though they may share the residence with other people. A primary residence is considered to be a legal residence for the purpose of income tax and/or acquiring a mortgage.
Criteria for a primary residence consist mostly of guidelines rather than hard rules, and residential status is often determined on a case-by-case basis.
Usage examples of "primary residence".
Most chose one primary residence, and used two or three others as occasion suited.
The EIA resold the Pittsburgh real estate for a dollar to anyone who pledged to make the home his or her permanent primary residence.
Born too late to experience the insult of segregation, she'd always thought of school as her second home, and after her father's brutal murder by Klansmenan act in itself an aberrant throwback of a hate crime that she'd never been able to fully erase from her mindMildred had come to rely on the educational system more and more as her primary residence as she grew older.
After all, this was both their primary residence and place of business.
Though the Grand Council still met here annually, and Castle Afon was still the Roidhun's official primary residence, the bulk of government business was transacted in antipodal Tridaig.