Định Nghĩa và Ý Nghĩa của "[go] off on a tangent"

What is the origin of the idiom "go off on a tangent" and when to use it?

The idiom "go off on a tangent" likely originates from the geometric concept of a tangent line, which touches a curve at a single point without intersecting it further. It is used to emphasize the idea that the person has deviated from the main topic and is now exploring a related or unrelated idea or subject.