Definition of "pyrophoric" [pyr•o•phor•ic]

• Spontaneously igniting in air. (adjective)
• Producing sparks by friction. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The company got a chance to show that when a customer had an accidental release of a "pyrophoric" gas that can ignite on contact with air."
• "Depleted uranium is "pyrophoric", which makes it uniquely effective at piercing hard targets, because upon impact, it immediately burns, vaporizing the majority of its bulk and leaving a hard, thin, sharpened tip - and large amounts of radioactive particles suspended in the atmosphere."
• "Finely divided uranium powder is pyrophoric, meaning it will ignite spontaneously at room temperature."