By Dawknin’s original definition (cultural) memes are ideas, behaviors, styles, or practices that spread within a culture by imitation (Greek mimema, meaning “imitated”) and carry symbolic meaning. Some examples would be the “Keep Calm And Carry On” posters during WW2, the concept of the “American Dream” or toasting with glasses.
However in this context we’re talking about internet memes which is not synonymous with cultural memes. An internet meme is a picture or video that is funny, ironic, or relateable.
Eh it absolutely is synonymous. And in the broader point that Dawkins made that you are missing out on is that evolution can act on these units. Since there is a selective pressure we should hardly expect them too look the same over time unless they are particularly well suited, case in point: