Stephanie Kwolek Invented This Bulletproof Fabric
Puzzle 20 of Yoga Hard Pack
Question is: Stephanie Kwolek Invented This Bulletproof Fabric
and the answer is: KEVLAR
Word Meaning:
KEVLAR — (uncountable) (Fabric, cordage, etc made of) aramid fiber, an exceptionally strong, light, man-made fibre used to strengthen cables and sheet materials, e.g. in stab-resistant vests.
Definitions from Wiktionary.