tangent

tangentti puhekieltä A straight line touching a curve at a single point without crossing it there.
puhekieltä A function of an angle that gives the ratio of the sine to the cosine, in either the real or complex numbers. Symbols: (m), (m).
A topic nearly unrelated to the main topic, but having a point in common with it.

I believe we went off onto a tangent when we started talking about monkeys on unicycles at his retirement party.

Jon & Kate Plus 8 is a show based on two facts: (1) Jon and Kate Gosselin have eight children, and (2) the word ‘Kate’ rhymes with the word ‘eight’. One suspects that if Kate were ever to have another child, a shady network executive would urge her to put it in a binbag with a brick and drop it down a well. But this is just a horrifying tangent.

Differentialregning kan fortolkes som forsøget på at bestemme en tangents hældning.

Differential calculus may be interpreted as the attempt to determine the slope of a tangent.