The research aims to create a formal definition of “Internet Meme” (IM) that can be used to characterize and study IMs in academic contexts such as social, communication sciences and humanities. Different perspectives of the term meme were critically analysed and contrasted, creating a contemporary concept that synthesizes different meme theorists’ visions about the term. Two different kinds of meme were found in the contemporary definitions, the meme-gene, and the memevirus. The meme-virus definition and characteristics were merged with definitions of IM taken from the Internet in the light of communication theories, in order to develop a formal characterization of the concept. Lastly, the use for characterization and research of the developed concept is exemplified by analysing two internet memes. Palabras claves: Meme, Internet Meme, Lamarckism, Darwinism, Viral Propagation (Media).