Plural of “family”

The plural of family is families.

Why

"Family" comes from Latin "familia," which originally referred to an entire household, including servants and slaves, not just blood relatives — a much broader social and economic unit than the modern sense of parents and children. English borrowed the word through this Latin root and applied the standard consonant-plus-y plural rule, giving "families."

The meaning has narrowed considerably since the word entered English: "familia" in ancient Rome centered on the household as an economic and legal unit under one head, while "family" in modern English usually centers on kinship and emotional bonds, a genuine semantic shift that happened gradually over centuries even as the plural spelling itself stayed perfectly regular throughout. English also uses "family" in biological classification (a taxonomic rank between order and genus, as in "the cat family"), a scientific sense borrowed by extension from the everyday kinship meaning once naturalists began organizing living things into nested groupings resembling human genealogical relationships.

Usage note

"Families" is standard in every context, from casual conversation about relatives to sociological and legal writing discussing household structures and family law. In British English specifically, "family" as a collective noun can take either a singular or plural verb depending on whether the family is treated as a single unit or as its individual members ("the family is arriving" versus "the family are arguing among themselves"), a flexibility American English generally doesn't share, defaulting instead to the singular verb.

Social scientists and legal scholars distinguish several formal categories under the broad plural "families," nuclear families, extended families, blended families, and single-parent families among them, each a precise sociological term describing a different household structure, though grammatically all take the same regular consonant-plus-y plural. The Latin root's original economic sense, an entire household unit including servants under one legal head, survives today mostly in specialized historical and legal writing about ancient Rome, having almost entirely given way in everyday modern English to the kinship-based meaning most speakers now take for granted.

Common real mistakes

As with other consonant-plus-y nouns, the error to avoid is "familys," adding -s without converting the y to i — a mistake that shows up occasionally even among adult writers because the singular "family" is such a common, comfortable word that the spelling rule for its plural doesn't always get the same attention as rarer words. Writers should also be careful with the possessive plural, "families'" (belonging to multiple families), which is easy to confuse with the singular possessive "family's" in fast, casual writing.

The wider pattern

Spelling-wise, "family" behaves exactly like "city" or "party" under the consonant-plus-y rule, changing y to i before adding -es. Its Latin root, originally referring to an entire household staff rather than a set of relatives, is a good reminder that meaning can drift a long way over centuries while the grammar governing a word, its plural included, stays put.

Examples

• Several families gathered for the neighborhood potluck.
• The charity provides housing assistance to low-income families.
• Both families attended the wedding together.
• Many families struggled financially during the recession.
• The school serves families from three different districts.
• Extended families often lived together in previous generations.
• Local families volunteered to host the exchange students.
• The census tracks how family sizes have changed over decades.
• Refugee families resettled in cities across the country.
• Three generations of the same families still live on that street.
• Community centers offer free programs for families with young children.
• The report compared family incomes across several neighboring counties.
• Both families exchanged gifts during the holiday visit.
• The reunion brought together families from four different states.
• Several families shared a single bus to the fairgrounds.
• The clinic scheduled checkups for families throughout the week.
• The shelter matched each pet with a waiting family.