NOUN:
1. One's ancestors or their character or one's ancestral derivation: ancestry, birth, blood, bloodline, descent, extraction, genealogy, line, lineage, origin, parentage, pedigree, seed, stock. See KIN, PRECEDE.
2. A group of people sharing common ancestry: clan, house, kindred, lineage, stock, tribe. Idioms: flesh and blood, kith and kin. See KIN.
3. A group of usually related people living together as a unit: house, household, ménage. See GROUP.
4. One's relatives collectively: kin, kindred, kinfolk. See KIN.
ADJECTIVE: Of or relating to the family or household: domestic, familial, home, homely, household. See KIN, GROUP.
Doesn't define a number of people. So 2 people can be a family.