The index fell by more than 3%. The S&P 500 shed 1.53% to 2,839.43, on track for its steepest loss since June.
Global markets followed the downward trend.
Europe is now suffering, with virtually all major bourses down more than 1.2% in the first hour of trading.
The biggest driver for the market over the last week has been interest rates, which began spurting higher following several encouraging reports on the economy. But the Nasdaq has really taken it on the chin: It has plunged almost 8% already in October.
The Dow Jones industrial average tumbled more than 400 points to just below 26,000 at lows. The Dow's percentage decline doesn't crack the top percentage declines. That hadn't happened since August 2011.
Once-highflying tech has led markets lower as yields rise, with the 10-year Treasury note's yield reaching its highest point in more than a decade yesterday.
Tom Cahill of Ventura Wealth Management said investors were also unnerved by remarks from luxury company LVMH of a crackdown on some goods in China amid the country's bitter dispute with the United States.
Bloodbath then spread to Asia with China's most significant mainland index, the Shanghai Composite, losing more than 5%. The stock fell 15 per cent to 50 cents.
Some of the big losers were stocks that have scored double-digits gains earlier in 2018.
The White House says there is no reason for concern after US stocks suffered their worst loss in eight months Wednesday.
And the CNNBusiness Fear & Greed Index, which looks at the VIX and several other indicators of market sentiment, plunged into Extreme Fear mode.
Some experts said this isn't a time to panic. "As stocks go down, tech goes down more than the stock market".
"The selloff is healthy", Heider said.
The turbulence follows a recent winning streak for US economic readings, including a 50-year low for the unemployment rate and the best-ever gauge of service-sector activity.
Leighton Roberts, chief operating officer and co-founder of Sharesies, urged investors not to panic.
The latest sell-off comes after months of continuous stock market growth stoked by the investors' belief in "American exceptionalism", according to an analyst from investment bank Morgan Stanley.
Bond prices fell. The yield on the 10-year Treasury rose to 3.23 per cent.
"Short-term bonds are getting to be a compelling place to hang out", he said.
As a five-day market slump raises concerns that the record bull market may be ending, press secretary Sarah Sanders says, "The fundamentals and future of the US economy remain incredibly strong". The relative lack of volatility was a bit troubling.