What does affinity mean?
Affinity is a noun describing a natural liking, attraction, or sense of kinship between people, animals, or things. When two strangers meet and feel they understand each other effortlessly, we say they have an affinity; when someone takes to a subject or craft instinctively, we say they have an affinity for it. The word also has precise technical uses: chemists speak of chemical affinity to describe why certain substances readily combine, and lawyers use affinity to mean kinship created by marriage, as distinct from consanguinity, kinship by blood. Derived from Latin through Old French, the word entered English in the late fourteenth century and has since broadened from its original sense of family connection into a general term for any deep-seated compatibility or likeness. Affinity carries warm, positive overtones in everyday use, suggesting harmony rather than mere similarity, and remains a versatile word in both casual conversation and scholarly writing.
A natural liking, attraction, or feeling of kinship between people or things.
"She felt an instant affinity with her new colleagues."
Most common everyday sense; warm and positive in tone.
A close resemblance or structural relationship between things, especially in scientific contexts such as chemistry or biology.
"The two species show a striking genetic affinity."
Frequent in technical and academic writing.
Relationship by marriage, as distinguished from blood relationship (consanguinity).
"Under canon law, affinity barred marriage between certain relatives of one's spouse."
Chiefly legal, ecclesiastical, and genealogical usage.
The plural is regular and commonly used when referring to multiple connections or likenesses, e.g. shared cultural affinities.
"The study compared the affinities between several related dialects."
The word 'affinity' once described something almost magical: alchemists believed certain substances had an 'elective affinity' that made them irresistibly drawn to combine — the same pull Goethe turned into a famous novel about doomed love.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of affinity
Affinity derives from the Latin affinitas, built on affinis, meaning 'neighboring' or 'related by marriage', from ad- ('to, toward') plus finis ('boundary'). It passed into Middle English via Old French in the late fourteenth century, where it first denoted kinship by marriage as opposed to blood relationship. Over time the sense widened from this legal and familial meaning to describe any natural attraction or close resemblance, including the scientific notion of chemical affinity. Cognates include French affinité and Spanish afinidad, both preserving the same Latin root.
How affinity is actually used
Affinity is slightly formal but widely used across registers, from everyday talk about personal chemistry to technical contexts like chemistry ('chemical affinity') and law ('affinity' meaning marriage-based kinship). It carries warm, positive connotations when applied to relationships, and neutral, descriptive connotations in scientific use. In legal and genealogical writing it is often paired explicitly with its opposite, consanguinity.
Easily confused with affinity
Infinity is a mathematical concept meaning limitless or endless quantity, while affinity is a noun describing a natural liking or kinship — the two share only a similar spelling and ending.
An affectation is artificial behavior adopted to impress others, whereas affinity is a genuine, natural feeling of connection.