Kind of a short one this week. My mind’s not fully back from vacation yet.
Merge showed up in the mid seventeenth century, so not all that long ago in etymology terms. It comes from the classical Latin mergere, which actually means things like immerse, dip in, plunge, or…drown. This is turning out to be my kind of word! It’s thought to come from the Proto Indo European mezg-, which means dip or plunge, where it was rhotacized, which basically means that they shoved an R in there for no particular reason. As to why it means combine these days, it probably is because in the eighteenth century it became a legal term for “absorb an estate, contract, etc. into another”. I guess that’s plunging in?
Emerge showed up in the mid sixteenth century, making it older than merge up there. It comes from the Middle French émerger and classical Latin emergere, rise or bring forth. See, the e comes from ex-, which means out here, while the merge is dip in. So instead of dip in, it’s dip out. Or dip in out? And there’s also emergency, which also comes from emergere. Just with a -ency after it. I guess an emergency is something that rises up suddenly.
Finally, submerge showed up in the seventeenth century from the French submerger and classical Latin submergere, sink. Pretty straight forward here. The sub- means under, so with merge it’s to dip or plunge under. I think this one made more sense than the other two.