the.com/housemate

means A person who shares your home and household duties (in theory) without sharing your family or romantic relationship with you.

from A plain English compound, stitched together from 'house' (Old English 'hūs') and 'mate,' meaning companion or fellow — a word whose own roots trace to Old English/Germanic terms tied to sharing food at the same table. 'Housemate' itself is a relatively modern formation, rising alongside shared urban living and roommate culture, as English needed a tidy label for 'person I live with but did not marry, birth, or befriend by choice alone.'