Noun
A curve of winding number 2 (around the observer)
English Wikipedia has an article on:winding numberWikipedia
winding number (plural winding numbers)
(geometry, topology, mathematical analysis) The total number of times a given curve travels counterclockwise around a specified point.
If a string has momentum p and winding number n in one description, it will have momentum n and winding number p in the dual description. Source: Internet
Therefore the winding number of the curve around zero should never change. Source: Internet
This is thus a generalization of winding number to higher dimensions. Source: Internet