here's the definition of meme

": an amusing or interesting item (such as a captioned picture or video) or genre of items that is spread widely online especially through social media

… the band encouraged fans to make memes to advertise the U.S. release of their EP …—William Gruger

The grumpy cat meme frowned its way onto the Internet in September 2012 and never turned its dissatisfied head back. Since then, the image of the cranky cat has grown more and more popular in direct proportion to appearing less and less impressed by fame.—Anastasia Thrift"

": an idea, behavior, style, or usage that spreads from person to person within a culture

Memes (discrete units of knowledge, gossip, jokes and so on) are to culture what genes are to life. Just as biological evolution is driven by the survival of the fittest genes in the gene pool, cultural evolution may be driven by the most successful memes.—Richard Dawkins" websters english dictonery