To help me build my vocabulary, I'm taking the plunge into nerddom. I'm putting post-it notes on everything in my modest little cottage, with their Esperanto name.

When I got to FIREPLACE, I thought the word would be fajrejo. But the vortaro gives kameno for the word. Just for kicks, I decided to look up fajrejo in the Eesperanto side and got the word hearth. I kind of thought the words in English were the same, but apparently, according to Webster's a hearth is the floor or a brazier. And a fireplace is the entire structure inclusive of the hearth.

SO to the Eo-Eo section of votar the definton of kameno is:

loko en cxambro kie povas esti fajro sen dangergxero.

A place in a room where fire an be without danger.

loko en kiu fajro brulas.

A place in which a fire burns.

That brought back to mind a brazier, which the vortaro renders as either bragxujo (coal-container), fajrkorbo
(fire basket), or latunisto, which I'm guessing is a brass smith.

Checking the word fajrujo, I get firebox, which according to MW is the part of broiler where the fire burns.

I'm guessing, since mantel is kamenbreko that kameno is the word I was looking for.

Am I overthinking this?

You're looking at a definition that is simpler than what you're really after.

The short answer is that a kameno is a fireplace.

The long answer is that a beginner's dictionary might define a "kitchen" as "a place where you cook" -- therefore you could easily say, well I can cook on an stovetop, is a range also a kitchen? You are overthinking the definition, which has simplified things to make the definition easier to understand.

If you are anxious to get a good handle on vocabulary, you might want to head over to vortaro.net, the online version of the most extensive Esperanto-Esperanto dictionary, the PIV. You can log in using your lernu account details (the sites are linked).

I hopped on over there and found this, which I think you will find to be a more satisfying definition:
[quote=url=http://vortaro.net/#kameno]PIV[/url]]
1 Parto de ĉambro tiel masonita, ke oni povas tie bruligi fajron sen danĝero de incendio aŭ asfiksio: la kastelaj kamenoj estas ofte ornamitaj per skulptaĵoj; la fratin’ sidis antaŭ la kamenoZ; faru fajron sur la kameno; fumnigrigita profundo de malplena kameno; du sinjoroj en unu bieno, du mastrinoj ĉe unu kameno neniam vivas sen reciproka malbeno.
2 Tia sama masonaĵo, interne de kiu oni adaptas fornon, stovon ks: brika, kahela, marmora kameno. ➞ kamenbreto, kamenkapuĉo, kamentubo, kamentubisto.[/quote]1. A part of a room built by masonry, such that you can burn a fire there without danger of fire or asphyxiation
2. That same kind of masonry construction, in which one adapts an oven, stove, and so forth

So basically - this word kameno can refer to a fireplace, it can refer to a hearth (only in the sense of a floor where a fire can safely be built). It is not a brazier.

erinja:So basically - this word kameno can refer to a fireplace, it can refer to a hearth (only in the sense of a floor where a fire can safely be built). It is not a brazier.

So kameno = fireplace. So what does fajrejo =?

FoxtrotUniform:

erinja:So basically - this word kameno can refer to a fireplace, it can refer to a hearth (only in the sense of a floor where a fire can safely be built). It is not a brazier.

So kameno = fireplace. So what does fajrejo =?

Fajrejo would be a word with such a generic meaning that English might not even have a single-word translation. It's a place for a fire. It could be a generic word encompassing fireplaces, outdoor fire pits, etc. Any place where you might build a fire would qualify as a fajrejo.

You will find this with some root+suffix combinations. Some will have a fixed meaning (malsanulejo is not just any place for sick people, it is a hospital) and some will have a relatively broad meaning that will depend on context (an "aŭtejo" is a place for cars but doesn't specifically indicate a garage or any special type of place for cars).

You'll learn these through experience.

erinja:

FoxtrotUniform:

erinja:So basically - this word kameno can refer to a fireplace, it can refer to a hearth (only in the sense of a floor where a fire can safely be built). It is not a brazier.

So kameno = fireplace. So what does fajrejo =?

Fajrejo would be a word with such a generic meaning that English might not even have a single-word translation. It's a place for a fire. It could be a generic word encompassing fireplaces, outdoor fire pits, etc. Any place where you might build a fire would qualify as a fajrejo.

You will find this with some root+suffix combinations. Some will have a fixed meaning (malsanulejo is not just any place for sick people, it is a hospital) and some will have a relatively broad meaning that will depend on context (an "aŭtejo" is a place for cars but doesn't specifically indicate a garage or any special type of place for cars).

You'll learn these through experience.

Thanks. I figured out that kameno was a fireplace primarily because kamenobrako is mantel.

At first (on Duolingo) I thought this is so easy. Now I'm thinking I'm way over my head .

A course based on translating simple sentences back and forth doesn't leave a lot of room for nuance. Duolingo was never going to be a substitute for actual experience with the language. It's a good jump-start, though.

FoxtrotUniform:At first (on Duolingo) I thought this is so easy. Now I'm thinking I'm way over my head .

You mean with learning Esperanto in general? Or, do you mean that Duolingo is difficult?

Alkanadi: You mean with learning Esperanto in general? Or, do you mean that Duolingo is difficult?

I finished Duolingo in like two months. I'm not going through the Spanish section to try to (re-) learn Spanish (4 years in HS, 2 semesters in college).

The Duolingo course was pretty easy. I still get zinged on the difference between using Ke, or tiu for that, I don't have that down.

But learning vocabulary. It's almost as though if it isn't based on an English word birdo, fisho, hundo, kato, aligatoro, krokodilo or Spanish abelo (abeja), araneo (araña), azeno (asno), I had a great deal of difficulty learning it anaso for duck, strigo for owl, kuniklo for rabbit, etc.

So I'm trying to build up a vocabulary fairly quickly, but finding out the shortcuts don't always work. To forget is not malmemori, but forgesi. and a Fireplace is not a fajreho (fire + place) but a kameno.

Added to the fact that I have no one to practice spoken Esperanto with, and that Esperanto learning must take a backseat to my college studies and my job, it's becoming a bigger hassle, when I thought it would be about as simple to pick up as Pig Latin.

FoxtrotUniform:
So I'm trying to build up a vocabulary fairly quickly, but finding out the shortcuts don't always work. To forget is not malmemori, but forgesi. and a Fireplace is not a fajreho (fire + place) but a kameno.

Added to the fact that I have no one to practice spoken Esperanto with, and that Esperanto learning must take a backseat to my college studies and my job, it's becoming a bigger hassle, when I thought it would be about as simple to pick up as Pig Latin.

These things have thrown me as well. It's not that it's troublesome to remember forgesi (almost an oxymoron!), but that as you say, it bucks the expected vocabulary-building methodology. I still think Zamenhof chose correctly with forgesi.

I haven't solely relied on the agglutination idea, instead treating the acquisition of a basic vocabulary as I would learning the basics of any other language - word-for-word, without worrying about etymology or cognates from other languages. Things move faster though, since many of those words have easily-derived antonyms, so you learn two words at once in many cases.

FoxtrotUniform:So I'm trying to build up a vocabulary fairly quickly, but finding out the shortcuts don't always work. To forget is not malmemori, but forgesi. and a Fireplace is not a fajreho (fire + place) but a kameno.

Esperanto is definitely not like Pig Latin, it is a full language, even if it is easier than other languages.

This may not be so comforting when you are using Duolingo (which is after all, graded by a computer) - almost surely, Duolingo will mark you wrong if you say "malmemori" instead of "forgesi".

But in real life, you could definitely say "malmemori" and be understood. It's not really the preferable word, sure, but you will be understood. This is a tremendous advantage to Esperanto. These workarounds are hugely helpful when learning vocabulary and gaining experience. If you don't know a word, you can build one, and even if what you come up with is not the usual word for something, you will be understood. If you're speaking Spanish and can't think of the word for a faucet, you might be out of luck. If you're speaking Esperanto, and you can't come up with "krano", you might come up with, say, "akvoeligilo" (akv/o/el/ig/il/o), and in context, someone would know what you were referring to (and maybe supply you with the right word, because akvoeligilo is a bit of a mess).

You could say "fajrejo" and in context it would be understood that you mean fireplace. Like I said, it can mean fireplace, it is just a more general word than "kameno". It would not be wrong to use it.