In the comments to the previous Ask Etymology Ethelwulf post, In Which I Gave The True Etymology Of The World "Umbrella," a commenter asked me to explain "agnostic," "helicopter," "amnesia," and "pregnant." I did so in the comments, but who reads the comments anyway? So I thought these new etymologies (with minor alterations) were worth posting in the main text:
"Agnostic" is from "agnus" (lamb) + "stick" — lamb on a stick; this is a derogatory term for unbelievers, dating back to ancient times in the Middle East, similar to the modern derogatory term "cafeteria Catholicism."
No, just joking! That was obviously made up. Actually, the "agnus" part is real, but the second part is from "Stygis," the river Styx of the underworld. Originally the label "agnostic" wasn't applied against members of all religions, but just those who thought that Christianity, with its specific miracles like the Resurrection, was unprovable. Early Christians were horrified by this, not because it was unbelief — that was of course the most common view in ancient times — but because it was the refusal to take a stand on an important spiritual question. Remember how, in Dante's Inferno, there's a special place just outside of Hell reserved for the cowards, rejected by Heaven and not accepted by Hell, who didn't take a stand in life? That has direct roots in the beliefs of the early Christians, who taught that those who neither believed nor disbelieved would be worse than damned — in classical metaphorical terms, stranded at the Styx (i.e., not allowed to cross the Styx into the underworld) — by reason of the lamb of God ("agno-Stygian" or "agnostycus").
"Helicopter" is from "helio-" (sun) + "Copt" — a reference to early Christian writings of the Patristic period (written in Coptic by Church Fathers living in Alexandria, and possibly inspired by ancient Egyptian sources) in which the souls of the dead were depicted traveling up to the sun in machines powered by angel wings ("heliocoptic transfiguration").
"Amnesia" comes from the Latin "amnis" (plural "amnes"), meaning "river." Recall that (while "denial" is not a river in Egypt) forgetfulness, to the ancients, was a river named Lethe; so to forget was to be "taken by the river" ("fluitare secundum amni Lethe"), and "amnesia" was just the abstract-noun form of that concept.
"Pregnant" is from "precor" (the Latin verb "to entreat, pray for, wish for," hence the Italian expression "prego!" and our modern word "prayer") + "nans, nantis" (the present participle of the Latin verb "no, nare," meaning "to swim"). This isn't too hard to understand — any expectant parents wish that their child will be born, and the traditional metaphor for birth was swimming (Ausschwimmung in the archaic Germanic sources).
You can check out the comments to the original post, where I also explain the etymology of the word "Shhhh."