- tangent (adj.)
- 1590s, "meeting at a point without intersecting," from L. tangentem (nom. tangens), prp. of tangere "to touch," from PIE base *tag- "to touch, to handle" (cf. L. tactus "touch," Gk. tetagon "having seized," O.E. ŝaccian "stroke, strike gently"). First used by Dan. mathematician Thomas Fincke in "Geomietria Rotundi" (1583). The noun also is attested from 1590s; extended sense of "slightly connected with a subject" is first recorded 1825.