Meme

From Merriam-Webster's Word-of-the-Day service:

The Word of the Day for August 18 is:

meme \MEEM\ noun
: an idea, behavior, style, or usage that spreads from person to person within a culture

Example sentence:
"Blogs are an interesting way... of seeing which ideas, memes, trends and news events are getting the most comment." (Clive Thompson, quoted in the Sunday Tribune, February 6, 2005)

Did you know?
In 1976, British scientist Richard Dawkins wrote The Selfish Gene, and in his book he defended his new creation, the word "meme." Having first considered, then rejected, "mimeme," he wrote: "'Mimeme' comes from a suitable Greek root, but I want a monosyllable that sounds a bit like 'gene.' I hope my classicist friends will forgive me if I abbreviate 'mimeme' to 'meme.'" The suitable Greek root was "mim-," meaning "mime" or "mimic." Dawkins's "mimeme" was formed from "mim-" plus "-eme," an English noun suffix that indicates a distinctive unit of language structure (as in "grapheme," "lexeme," and "phoneme"). "Meme" itself, like a good meme, caught on pretty quickly, spreading from person to person as it established itself in the language.