What is the meaning of NYLON at cable?

Nylon is a strong, tough fiber which has excellent abrasion resistance. In fact, in combination with nylon lacquer, it forms probably the best braid lacquer team in this respect. Nylon is inert to fungus. Nylon is flammable, but much slower burning than other organic fibers. It has thermal properties which permit its continuous use at 105°C. Nylon is widely used both as a reinforcement for elastomeric jacketed cables and as outer coverings for many wire constructions, such as those specified in MIL-W-5086.

source : cable book HEADQUARTERS, U.S. ARMY MATERIEL COMMAND