Apple's latest iOS update includes a number of bug fixes and performance improvements, but the new additions getting the most attention are the emojis added to the system's vocabulary — including a hand making the "metal horns" sign.

A symbol familiar to pretty much everyone who's ever rocked or been rocked, the horns have their roots in ancient religious rituals and have been assigned a wide variety of meanings over the years, but for contemporary Westerners, they're basically shorthand for metal — a shift widely credited to Ronnie James Dio, who started using the gesture on stage after taking over for Ozzy Osbourne in Black Sabbath.

As Dio explained in a Metal Rules interview, he adopted it from his Italian grandmother, who used it as a superstitious way of giving or warding off the evil eye. "It's just a symbol, but it had magical incantations and attitudes to it and I felt it worked very well with Sabbath," said Dio. "So I became very noted for it and then everybody else started to pick up on it and away it went. But I would never say I take credit for being the first to do it."

Until now, computer users wanting to wave their horns with a keyboard have had to type them out as "\m/," but now iOS 9.1 adopters have a fancier option to choose from — along with more than 180 other new emojis for other occasions, including a taco, a burrito and a raised middle finger. Check out the complete list of the new additions.

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