There is no evidence for the popular belief that "nylon" is a contraction of "NY" (for "New York") and "Lon" for "London", the two cities where the material was first manufactured. In 1940 John W. Eckelberry of Du Pont stated that the letters "nyl" were arbitrary and the "on" was copied from the names of other fibres such as cotton and rayon. A later publication by Du Pont (Context, vol. 7, no. 2, 197
explained that the name was originally intended to be "No-Run" ("run" in this context meaning "unravel"), but was then modified to avoid making such an unjustified claim and to make it sound better. The story goes that Carothers changed one letter at a time until Du Pont's management were satisfied.
Another popular belief is that nylon stands for "now you, lazy old nippon," as nylon was developed in the 1930s. In this sentence nippon stands for Japan, as in the 1930s, the decade in which nylon was developed, a chemical "war" was taking place between the US and Japan.