A word for kin, household, and kind
In present-day English, family most often names the people closest to you by blood, marriage, or adoption: parents and children, and sometimes a wider circle of relatives. It can also mean lineage, a household living together, or, in looser talk, any tight group that behaves as kin. Biology uses the same noun for a rank between order and genus; linguists use it for languages that share a parent. Those later senses rest on one idea: a set bound by common origin. The origin of the word family is less sentimental than that modern picture suggests.
A late medieval borrowing
English did not inherit this noun from Old English. It arrived as a loan in the late Middle English period. The Oxford English Dictionary places the earliest evidence in 1388; other dictionaries group the first uses in the later fourteenth or early fifteenth century. The immediate sources are Latin familia and French famille. Historical dictionaries treat the English form as coming from both: a learned Latin loan shaped by the French word already current on the Continent.
Middle English spellings include familie and famylye. Before that borrowing settled, speakers already had native vocabulary for the same social unit. Latin familia was routinely glossed with Old English hired or hyred, and with hiwan, hiwscipe, and hiwræden, words for the members of a household or a religious house. Those native terms sit with words for home and for married partners in other Germanic languages. A fifteenth-century glossary even rendered the Latin with menge, from Anglo-French maisnie, the retinue around a lord. Family eventually pushed most of those older labels out of ordinary speech.
Household, not parents and children
Latin familia did not, in classical usage, mean what English speakers now picture first. Its core was the household as an establishment: the enslaved staff and other servants attached to a house, then by extension everyone under that roof, the estate, and the property that went with it. Roman writers more often used domus when they meant the house as a place of kin. The legal figure of the paterfamilias headed a familia that could include free descendants, wives brought in by marriage or adoption, and enslaved people, all under one authority. Historians of Roman society still note that the Latin noun is a poor match for the modern nuclear family.
The Latin word is built as an abstract noun on famulus, a servant or slave, with the suffix that yields familia. English familiar comes from the related adjective familiaris, originally of one's own household, later private, then intimate. That path is why familiar can still mean both well known and, in older use, a household attendant.
An uncertain deeper root
How far back famulus goes is not settled. Ancient Roman scholarship, preserved by Festus, derived it from Oscan famel, a word for a slave, and treated familia as following from that. Oscan does attest famel and a household word famelo, and Umbrian has related forms, so the Italic cluster is real.
Modern etymologists do not all tell the same story. Some references simply call the origin of famulus unknown. Others reconstruct a Proto-Italic form and, more tentatively, a Proto-Indo-European formation from a root meaning to put or place, linking the Latin servant word to ideas of a settled household. A further view reverses the usual derivation and treats famulus as a back-formation from the household noun rather than its source. Older classical handbooks sometimes rejected the slave etymology altogether and preferred a sense of people belonging to a house. The honest account is that the Italic words are secure and the deeper Indo-European step is a hypothesis, not a closed case.
Cognates of the English noun are easy to see once Latin is in view: French famille, Italian famiglia, Spanish and Portuguese familia, Romanian familie. They are sisters from the same Latin stock, not independent Germanic inheritances.
From servants to kin, then to classes of things
The first English sense, in the fifteenth century, was the staff of a household: people in someone's service. That meaning is now archaic, but it is the one that sits closest to Latin. By the 1540s the word could name everyone living under one head, parents, children, and servants together, and sometimes lodgers as well. Lineage, a house descending from a common ancestor, is recorded from the 1580s. Only in the seventeenth century does the dominant modern sense come into clear view: parents and their children, whether or not they share a roof, and, more loosely, people related by blood beyond that circle. One dictionary dates the parent-and-child sense as early as 1602; another places a clear record in the 1660s. The dates differ by a few decades, but the direction of change is the same.
Once the word meant a kindred set, it was available for any grouping judged to share a nature. That use is attested from the 1620s. Naturalists then took it into classification. English scientific writing uses family as a rank between genus and order from the mid-eighteenth century; botanists had already experimented with Latin familia for plant groups in the late seventeenth century. Language families and instrument families are later applications of the same metaphor.
What the older sense still shows
If one fact keeps the history from collapsing into a simple story of blood ties, it is the earliest English meaning. The noun arrived as a word for the people who served a house, not for a married pair and their offspring. Kinship filled the word later. That is why family and familiar still sit beside each other: both began as names for belonging to a household, and only afterward did one become the ordinary English word for relatives.