Wiktionary
n. A supplemental food in bar form, containing cereals or other high-energy foods.
Wikipedia
Energy bars are supplemental bars containing cereals and other high energy foods targeted at people who require quick energy but do not have time for a meal. They are different from energy drinks, which contain caffeine, whereas bars provide food energy.
Usage examples of "energy bar".
He'd given her a sip of water from his canteen and some kind of high-protein energy bar from a pocket of his vest.
He looked down the trail and put the energy bar wrapper in his pocket.
Half an energy bar had provided a challenge for his teeth, and precious little for his stomach.
Randy parked his bike upright on its stand, then used his alla to make himself an energy bar and a can of Bharat Jolly-Zest soda, an anise-flavored Indian soft drink he'd become fond of in Bangalore.
They'd each been given an energy bar and a carton of apple juice when they'd been wakened, but it hadn't been enough, for him at least.
Otherwise, Nigel will keep an eye on you and that energy bar will be delivered to your cell, oh, I'd say about an hour, maybe two, after you've given up on it.
The energy bar wasn't sitting well in her stomach, which made her wonder just how long it had been since the vending machine had been serviced.
She tapped a finger on his scanner, then pulled out her energy bar.
She grabbed a cheese phyllo and an energy bar at a QuickMart and settled for a tube of Pepsi rather than their notoriously poisonous coffee.