An egg cream is a kind of sugary dessert drink that contains neither eggs nor cream. The cream part exists because it's based on a more expensive version of the beverage that did contain cream, but for egg we'll have to dig deeper, to its origins in the Ashekenazi Jewish community in New York City. One theory is that it's actually a corruption of the Yiddish word echt, meaning "genuine" or in this case something more along the lines of "good". That would trace to German echt, which translates to "real" and derives from Proto-Germanic aiwaz ("long time") and Proto-Indo-European hoyu. Alternatively, it could also be because it's modelled on a drink that did include egg yolks; both explanations are unconfirmed. We do know for sure, though, that after its first attestation in 1841, literary usage of the term skyrocketed, peaking in 2004.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.