(immunology) the attraction between an antigen and an antibody
"The strength of the affinity determines how tightly a specific antibody binds to its corresponding antigen during an immune response."
(anthropology) kinship by marriage or adoption; not a blood relationship
"In the study of family structures, the anthropologist noted that affinity refers to relationships formed through marriage or adoption rather than shared bloodlines."
(biology) state of relationship between organisms or groups of organisms resulting in resemblance in structure or structural parts
"in anatomical structure prehistoric man shows close affinity with modern humans"
the force attracting atoms to each other and binding them together in a molecule
"basic dyes have an affinity for wool and silk"
inherent resemblance between persons or things
"The two musicians shared an affinity, as their playing styles naturally mirrored each other without any prior rehearsal."
a natural attraction or feeling of kinship
"an affinity for politics"
"the mysterious affinity between them"
"James's affinity with Sam"
A natural attraction or feeling of kinship to a person or thing.
"She felt an immediate affinity for her new neighbor, who shared many of her hobbies and values."
In plain English: Affinity is a natural liking or connection you feel toward someone or something without having to try hard for it.
"She has an affinity for cooking and loves spending weekends in the kitchen experimenting with new recipes."
Usage: Use affinity to describe an innate liking or connection between people, ideas, or objects based on shared characteristics. It is often confused with sympathy, but while sympathy implies pity for someone's suffering, affinity suggests a genuine bond or natural compatibility.
The word affinity entered English via the Middle English form affinite, which was borrowed directly from the Old French term affinité. It originally described a state of being related or connected in nature, much like its modern usage implies.