Warning: if you are not fascinated with words, if your family has not given you a dictionary of Indo-European roots as a Christmas present, you may want to read something else.

The etymology of etymology:

etymology

late 14c., ethimolegia "facts of the origin and development of a word," from O.Fr. et(h)imologie (14c., Mod.Fr. étymologie), from L. etymologia, from Gk. etymologia, properly "study of the true sense (of a word)," from etymon "true sense" (neut. of etymos "true, real, actual," related to eteos "true") + -logia "study of, a speaking of" (see -logy). In classical times, of meanings; later, of histories. Latinized by Cicero as veriloquium. As a branch of linguistic science, from 1640s. Related: Etymological; etymologically.

From The Online Etymology Dictionary.

I’ve met one etymologist in my life.  I took a survey of western literature that substituted for a philosophy class under her.  I only found out her background when I misspelled “guardian” by switching the “u” and “a” on a Blue Book exam.  She wrote the etymology of the word in the margin and pointed out the connection to words like warden and warranty.  Fascinating!  Here was one of those people who actually write that little blurb that goes in a Webster’s Unabridged Dictionary entry.

It’s interesting that the form of the word etymology has changed little from the Greek origin while its usage has changed from a study of meaning to one of history.

Etymology is a sort of archeology of words.  Having written this I’m almost overwhelmed by an urge to go look up the origins of archeology.

Speaking of overwhelm, have you heard anyone say, “I was underwhelmed?”  Underwhelmed is used in the context of unimpressed.  Here is why it makes no etymological sense.

Overwhelm is what I like to call an orphan word.  It lives, but its parent whelm is dead, no longer in use. 

overwhelm

early 14c., "to turn upside down, to overthrow," from over + M.E. whelmen "to turn upside down" (see whelm). Meaning "to submerge completely" is mid-15c. Perhaps the connecting notion is a boat, etc., washed over, and overset, by a big wave. Figurative sense of "to bring to ruin" is attested from 1520s. Related: Overwhelming; overwhelmingly.  From the online etymology dictionary.

The use of underwhelm appeared in 1956 as a facetious comment.  It is currently considered slang.

My father used to use the term mare’s nest that was a puzzle to me.  It would be used to describe a terribly messy place.  Mare’s sleep in stalls not nests.  A few years ago the search began for the root of this form.  I started with nightmare, imagining that the mare might have the same root.  It seems that they do.

Nightmare is from night, straightforward, and mare, not.  Mare is an Old English form for a succubus, an evil spirit that comes in your sleep, lying on top of you and suffocating you.  It ultimately derives from the Indo-European root mer, to do harm, which is also the root of murder.

(The word nightmare makes its appearance c.1300 in the St. Michael (Laud) manuscript:

Þe luþere gostes...deriez men in heore slep...And ofte huy ouer-liggez, and men cleopiet þe niȝt-mare.
(The wicked spirits...injured men in their sleep...And often lay on top of men, and men called them the nightmare.) From wordorigins.org.)

 There are cognates of mare in other languages. My great grandfather was Austrian.  Perhaps “mare’s nest” was a transliteration of some word in German. Maybe it’s an old English term forgotten everywhere except in my family.  I’ve never heard anyone else say mare’s nest, but I’m guessing that it meant a goblin’s lair.

Other ideas are welcome, as well as news of this term in the speech of other families.