tangent

Where does the word "tangent" come from? It comes from Latin tangere, and was adopted directly into English (1590s).

Tangent’s story begins in Latin: tangere meant “to touch.” The root of 'tact', 'contact' and 'tangible'. It reached English by 1590s as tangent. 'go off on a tangent' dates from the 1700s. Today, tangent means a straight line that touches a curve at a single point without crossing it.

1. Stage 1 · Latin · ancient tangere "to touch", the root of 'tact', 'contact' and 'tangible'.
2. Stage 2 · English · 1590s tangent "a line touching a curve at a single point", 'go off on a tangent' dates from the 1700s.