Nylex was a type of clothing material.
History and specifics[]
In the year 2373, Julian Bashir and Jadzia Dax donned Starfleet nylex dry suits. The gloves made Jadzia's palms itch and a rolled up hood pressed against the back of her neck. Jadzia considered that Bashir probably liked wearing the nylex. (DS9 - Rebels novel: The Courageous)