Affine
/əˈfaɪn/noun
Relating to or having a close connection or affinity; in mathematics, preserving parallelism under a transformation.
Did you know?Its deepest root is the same Indo-European family behind words for a boundary or limit, which is why it evolved into the idea of being ‘related by marriage’ before becoming a technical term in math.
Etymological Timeline
Proto-Indo-European
PIE
*dʰeh₁-
“to put, place, set”
Latin
Latin
affīnis
“neighboring, bordering on; related by marriage”
Late Latin
Latin
affīnitās
“relationship by marriage; close connection”
Middle French
Old French
affin
“related, akin”
Late Middle English
English
affine
“closely related; later, in mathematics, preserving parallelism”