Ahmad Ali and his wife, Ghalzal, pick up three flat-screen televisions while shopping at a Target store just after midnight on Black Friday, Nov. 28, 2014, in South Portland, Maine. (AP Photo)

Ahmad Ali and his wife, Ghalzal, pick up three flat-screen televisions while shopping at a Target store just after midnight on Black Friday, Nov. 28, 2014, in South Portland, Maine. (AP Photo)

Millions of Americans hit the stores on the Friday after Thanksgiving, a day that has been given the name “Black Friday.”

Black Friday is seen as the start of the holiday shopping season, a time when U.S. retailers rake in 20 percent of the year’s profits. Many stores offer deep discounts to draw customers in and shoppers often line up early for a chance to grab one of the deals before supplies run out.

The National Retail Federation predicted that 140 million Americans would go shopping sometime during the three days after Thanksgiving.

Emotions and tempers can run high on Black Friday as customers race into stores once the doors open. In 2008, a worker at the Walmart discount department store died after a stampede of shoppers. In 2013, a dispute over a Walmart parking space led to a stabbing in Claypool Hill, Virginia.

“Shopping is no longer an event. It used to be about browsing, buying, and socializing. In the 1970s, shoppers became more interested in looking for a bargain and getting a free parking space over spending the day with family and friends,” said retail historian Michael Lisicky in an email. “Now the Internet, and let’s not forget membership warehouses, has turned retailing into a chaotic event. It’s about survival of the fittest and it makes the expression Black Friday all the more meaningful.”

Young adults might be reversing part of that trend. According to NRF, nearly eight in 10 people aged 18-24 years old, the highest of any age group, intended to shop over the weekend and their focus won’t exclusively be on nabbing a great deal.

“For younger shoppers, shopping on Thanksgiving and Black Friday is as much a social experience as it is a buying mission,” said Pam Goodfellow of Prosper Insights & Analytics, which conducted the NRF’s survey, in a press release. “While these shoppers may not have the biggest holiday budgets or the longest shopping lists, they still enjoy the ‘tradition’ of heading out with friends and family on two of retail’s most exciting shopping days.”

Shoppers wait to enter Macy's to kick off Black Friday sales in New York November 27, 2014. (Reuters)

Shoppers wait to enter Macy’s to kick off Black Friday sales in New York November 27, 2014. (Reuters)

Black Friday was not always associated with blockbuster deals, according to Lisicky, the author of several department store books including Wanamakers: Meet Me at the Eagle, Gimbels Has It!, and his latest release, Shop Pomeroy’s First.

“The original term ‘Black Friday’ referred to the 1869 gold speculation crisis so the term ‘Black Friday’ actually had its roots in economic chaos,” Lisicky said. “The phrase was an in-house term that surfaced in 1961 and was used by Philadelphia authorities to describe Center City traffic congestion from After Thanksgiving shoppers and those attending the Army Navy Game.”

These days Black Friday actually starts on Thursday. Many stores now open on Thanksgiving night.

Macy’s CEO Terry Lundgren estimated more than 15,000 people showed up to shop at the Macy’s department store in New York City when the doors opened Thursday evening. And it isn’t just the brick-and-mortar stores that draw crowds.

By Friday morning, Target stores, which sell everything from food, to household goods to electronics, reported a 40 percent increase in Internet shopping over last year, making Thanksgiving Day 2014 the retailer’s biggest online sales day ever. Target said the most growth in traffic and sales came from mobile devices. The hottest sellers included electronic tablets, cameras, vacuum cleaners and video game consoles.

While those numbers look good, opening stores on Thursday and offering deals online threaten to dilute the Black Friday brand.

“Is there still a Black Friday? Now it’s Black Thursday, or Black Thursday Eve,” Lisicky said. “There’s been tremendous sales growth online and in-store from last Thanksgiving to this Thanksgiving. But it’s no longer an orchestrated event and it’s future relies on being an event.”

Whatever the future holds, the Black Friday present looks promising for retailers. NRF expects overall holiday shopping sales rise 4.1 percent to $611.9 billion. That would end up being the largest increase since 2011.