What does “etymology” include?

etymology (n.) late 14c., ethimolegia "facts of the origin and development of a word," from Old French et(h)imologie (14c., Modern French étymologie), from Latin etymologia, from Greek etymologia, properly "study of the true sense (of a word)," from etymon "true sense" (neuter 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.

Source: Etymonline.com

etymology n. pl. et·y·mol·o·gies 1. The origin and historical development of a linguistic form as shown by determining its basic elements, earliest known use, and changes in form and meaning, tracing its transmission from one language to another, identifying its cognates in other languages, and reconstructing its ancestral form where possible. 2. The branch of linguistics that deals with etymologies.

Source: American Heritage Dictionary

As you can see from the etymology of the word 'etymology' and its current definition, both the origin and the different stages of development of its usage are part of the etymology of a word.

I'm curious how one describes the etymology of a word.

Unless you want a recursive definition of etymology, I am assuming you mean how to describe the origin or way a word has evolved over a period of time. Putting aside any 'common' words that can be used (history, evolution, roots, etc), here are a few more less known ones that might be useful:

Congenetic: (Adjective) Having a common origin. (See also: isogenesis)

• Chill and cool are congenetic words.

Monogenesis: Origin of diverse individuals or kinds (as of language) by descent from a single ancestral individual or kind

• Pixel and email have the same monogenic origin: computers.

Polygenesis: Development from more than one source. (See also: polyphyletic)

• The word computer has polygenic origins.

Fons et origo: (Phrase - Latin) Source and origin.

• Etymology is a fons et origo science.

Endogeny: (Adjective) Formed from within.

• Can't is an endogenic contraction of cannot.

Archology: (Noun) The science of origins.

• The etymology of words is an archological investigation.

Cryptogenic: (Adjective) Unknown/mysterious origin.

• The word the is cryptogenic.

États présents: (Phrase - French) An exhaustive summary of up-to-date knowledge about a subject, as opposed to new information or original thought.

• The états présents of the word etymology is...

Your question (etymology) is qualitative (not quantitative) and subject (not objective), so the answer could and would be different according to the answerer's point of view, but the following is helpful in terms of 'a clear and general definition':

1. Etymology is the study of the origins and historical development of words.
2. The etymology of a particular word is its history.

[Collins Cobuild Advanced Learner's English Dictionary]

Etymology itself has a rather unfortunate etymology. The -ology part is just Greek for 'words about', typical of all abstract fields of knowledge. But the etymon part is Greek for 'true name'; that is, the name that naturally refers to something, and therefore compels it.

The doctrine of True Names is part of magic, and is just as effective as any magic. Like other varieties, it involves words. Not surprising, since language is the reality that became mythologized as magic, especially deep knowledge of language (see the etymologies of gramarye, grimoire, or glamor, for instance, which are just old forms of grammar, but have acquired entrancing characteristics over the centuries).

So the Greeks believed etymologies were accounts of the True Name of something, and one still encounters the Etymological Fallacy, but one need not pay attention to it.

Today, etymology has several meanings, of which the dictionary segment is one. Every dictionary is different, of course, but they tend to copy one another, especially in things that are settled, and etymologies usually fall into that category.

The heyday of dictionary etymology of English is over. There are lots of issues, but they're pretty minuscule; unless you want to argue about Proto-Indo-European laryngeals or ejectives, the work has been done.

That leaves the question of what else etymology means, and where new ones come from. This reminds me of the time one of my brightest and most enthusiastic students wanted to know how you became a professional etymologist. Not an unreasonable question, in a reasonable world. But in this world, I had to tell them that there was no such thing as a professional etymologist. Etymologies were generated as needed, as part of the job of historical linguistics, especially the reconstruction of proto-languages.

To become a historical linguist, one must learn linguistics, naturally, but one must also learn a lot of older languages (the older the better), guess at their pronunciation (with lots of clues), and propose possible sound changes. Ethnography, phonetics, and history, natch. And if you're going far back, archaeology and genetics. It's, as they say, complicated.

But the easy way to look at it, and the way that always works in context, is to consider that the etymology of a word (or phrase, or suffix, or other discrete chunk of language) is basically just the story of the word. Whatever story means, it certainly involves history, and it may be as various as any story is.

Every word has its own story, which includes all of the billions of uses, in millions of mouths, in thousands of speech communities, over hundreds of years. And all of the uses it's been put to, and all of the lies and truths it's been associated with.

A story like that would take a long time to tell, even if we knew all of what's in it. The story of a word is much much longer and larger than the story of any single person, and we can't begin to describe any human scientifically.

So an etymology is an attempt to describe as much of the history of a word as is known, and is needed, and will fit in the space available.