1. noun /ˈtæn.dʒənt/
I believe we went off onto a tangent when we started talking about monkeys on unicycles at his retirement party.
b) In a right triangle, the ratio of the length of the side opposite the angle to the length of the side adjacent to the angle. Symbols: tan, tg <!This definition equivalent to the one above; it does not define a new sense of the word
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.
See Also: tangential
2. adjective /ˈtæn.dʒənt/
a) Touching a curve at a single point but not crossing it at that point.
b) Of a topic, only loosely related to a main topic.
Wikipedia foundation.