Apple's (AAPL) share of the tablet market dropped dramatically in the most recent quarter as a new Kindle offering from Amazon and advanced adoption of Samsung tablets running Google's (GOOG) Android operating system ate into the iPad's dominance, an analysis showed Monday.

Apple retained a majority of tablet market share in the third quarter of 2012, at 50.4 percent, but that was down markedly from 65.5 percent in the second quarter, according to a report from the International Data Corporation. The biggest gainers were Samsung, which increased from a 9 percent share in the second quarter to 18.4 percent in the third quarter after releasing its Galaxy Note 10.1 tablet in August; and Amazon, which increased from 5 percent to 9 percent despite releasing its newest tablet, the Kindle Fire HD, late in the quarter, on Sept. 14.

Apple released two new iPad models Friday, including the Cupertino company's first foray into the smaller tablet market, the iPad Mini. Apple announced that it sold 3 million iPads in the first three days of availability for the iPad Mini and the fourth-generation iPad, and IDC speculated that the quarterly showing was a

result of customers waiting for the new release.

"We believe a sizable percentage of consumers interested in buying an Apple tablet sat out the third quarter in anticipation of an announcement about the new iPad Mini," Tom Mainelli, research director for tablets at IDC, said in Monday's news release.

However, IDC's analysis did not show a slowdown in tablet sales overall; instead, tablet sales grew nearly 50 percent from the same quarter the year before and 6.7 percent from the second quarter.

Samsung specifically provided strong competition to Apple in the quarter, posting the largest share of the tablet market by any company not named Apple since the introduction of the iPad.

"Samsung took advantage of an opportunity in the second quarter," Ryan Reith, manager of IDC's Mobile Device Trackers program, said. "The company offers a wide range of tablet offerings across multiple screen sizes and colors, and that clearly resonated with more buyers this quarter. Its growth to 18.4 percent of worldwide market share during the quarter represents the first time a competitor has attained this level of share since the original launch of the iPad."

Samsung and Apple have staged a global legal battle in which Apple claims Samsung infringed on iPad and iPhone patents, copying popular elements of the devices in order to boost sales. Apple won a $1.05 billion verdict in a San Jose courtroom battle, which Samsung is now appealing.

Samsung and Amazon tablets utilize the Android operating system for their tablets, though Amazon uses a highly customized version of Google's OS and sells apps through its own online store instead of Google Play. Apple's late cofounder, Steve Jobs, famously denounced Google's operating system to his biographer, Walter Isaacson, saying that it copied Apple's mobile offerings.

"I'm going to destroy Android, because it's a stolen product. I'm willing to go thermonuclear war on this," he told Isaacson.

Apple announced in its earnings report last month that it sold 14 million iPads in the third quarter, a drop from 17 million sold in the second quarter, when the third-generation iPad was introduced.

Contact Jeremy C. Owens at 408-920-5876; follow him at Twitter.com/mercbizbreak.