Nerve gas, Weapon of chemical warfare that affects the transmission of nerve impulses through the nervous system.
According to Ryan Compton's Infinite Jest by the Numbers, Wallace used a vocabulary of 20,584 unique words to write the 577,608-word Infinite Jest. 10. 11. n+1 has a neat story about where the name for Michael Pemulis, Hal's drug-dealing friend at Enfield Tennis Academy, came from.
The longest word in the English language (leaving literature to one side for a moment) is a staggering 189,819 letters long. Or rather, it is and it isn't. The chemical formula for the protein otherwise known as titin runs to 189,819 letters, but whether this constitutes a 'word' is a moot point.