A book or other product that has sold in extremely large numbers.(noun)
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Use "megaseller" in a sentence
"This week I checked into the Freakonomics blog on the New York Times site for the first time in a while and saw that Venkatesh, who first came to popular notice when his work on the (lousy) economics of crack dealing was featured in that megaseller, has been guest-blogging about watching the fifth and final season with some self-described "real thugs" of his acquaintance."
"So why keep a spot for an author whose books aren't making the cash registers ring when the next "new" author could be a megaseller?"
"His direct ancestor is the legendary warlord Ieyasu Tokugawa, who established a dynasty that shut Japan off from the world for 250 years (you may remember him portrayed as the victorious Toranaga in James Clavell's megaseller "Shogun")."