Lookups spiked on December 11, 2012.
People are hearing and seeing the word a lot these days. Like holly and Christmas trees, poinsettias are a traditional sign of the holiday season.
A poinsettia is "a plant with large red, pink, or white leaves that look like petals" and is native to Mexico and Central America.
People look up the word partly because it's hard to spell. For example, the photograph here shows a supermarket trying two different versions. The spelling in the top sign ("pointsetta") is incorrect; the spelling in the bottom sign is basically right, though it should say "poinsettias" rather than "poinsettia's."
Poinsettia is an eponym – a word derived from someone's name. (Other plants derived from names are begonia, fuchsia, and narcissus). The American diplomat Joel Roberts Poinsett was stationed in Mexico, and brought the plant to the U.S. in 1825.