Nasdaq
Also called: NASDAQ, Nasdaq Composite, Nasdaq 100
Nasdaq is both a US stock exchange and the indexes named after it. The exchange was the first fully electronic one, which is why it attracted technology listings; the Nasdaq Composite tracks all its listed companies while the Nasdaq-100 tracks the largest non-financial ones. Because of that history the indexes are heavily tech-weighted, so 'the Nasdaq fell 3%' is usually a statement about a handful of very large technology firms.