My solution appEars To be Absent!

As f" solved for Saturn
and Cain reasoned Stairs
While one word you seek
Three this riddle bears:

Carved from a forest we lie
A road built of bone we supply
With great walls of black
We are known to attack
From the forest an echo replies

For a singular purpose we're made
To deny those of whom you're afraid
And provide peace of mind
Each day we're combined
With our partner who therein has stayed

At prominence ere the fall of Rome
We held the theaters, bridges and domes
In structures erected
We shan't be neglected
Lest one desires to topple our home

Hints:

The first stanza is describing the method with which this riddle was written. For instance, I thought of many things which referred to Saturn and described them. Though technically separate words (homonyms, in fact), the answer is just one.

By now you may have noticed that the second stanza is buried deep in metaphor. There is no real forest. There is no real road. There are no walls. They do attack, but not in a violent sense. The forest does respond to the attack with a sound, however.

A biologist may cringe at my use of the word "bone" in the second stanza. It shouldn't prevent anyone from solving it, but it is scientifically inaccurate, so I apologize to those feeling scrupulous.

• I like the title - very META. Aug 13, 2015 at 16:41
• If you like limericks, perhaps you can help Alconja clean up his answer for this rhyme Aug 13, 2015 at 19:31

I think it's just

Keys

As f" solved for Saturn
and Cain reasoned Stairs
While one word you seek
Three this riddle bears:

As the first hint suggests, each following stanza is a riddle pointing at the solution -- but describing a different word of the homonym-group.

Carved from a forest we lie
A road built of bone we supply
With great walls of black
We are known to attack
From the forest an echo replies

Piano keys: Once made of ivory (technically not bone, hence the biologist comment), the white keys form a "road" of sorts delineated by black keys that protrude from the keyboard like walls. When struck, they "attack" a "forest" of wires, which "reply" with a tone.

For a singular purpose we're made
To deny those of whom you're afraid
And provide peace of mind
Each day we're combined
With our partner who therein has stayed

Keys, as in the things that go in your pocket and unlock things. Similar to Kingrames's interpretation, but I thought of the "partner" as the lock, although there could be other possibilities. There is some ambiguity about "therein" as I at first thought it referred to "mind", then "day", but it doesn't actually seem to refer to anything, so I'm recklessly assuming it was used for cadence.

At prominence ere the fall of Rome
We held the theaters, bridges and domes
In structures erected
We shan't be neglected
Lest one desires to topple our home

Key stones, as Kingrames suggested.

• You have the answer, but I'll clear up some confusion.<br> 1. I intended the forest to represent the piano's wooden body, and for attack to literally be the key attack (a piano term).<br> 2. "Our partner who therein has stayed" was referring to the lock, which unlike the key (its "partner"), usually stays in one place, perhaps in a door/doorknob (hence "therein").. Aug 15, 2015 at 13:36
• Ah, I'd never heard the term "key attack" before, but I just knew "road built of bone" had to be ivory, somehow, especially after the third hint :) The lack of an antecedent for "therein" is just a nitpick. Aug 16, 2015 at 2:06

Forked off of Kingrames' partial solution:

The solution is

the idiom "under lock and key", meaning that something is very fiercely guarded

Carved from a forest we lie
A road built of bone we supply
With great walls of black
We are known to attack
From the forest an echo replies

Underwater. Ships are carved from wood, which comes from a forest. When they sink, they supply a road of bones to the bottom of the ocean. walls of black = darkness. The second forest is the forest on the bottom of the ocean. Seagrasses, kelp, maybe even a coral reef.

For a singular purpose we're made
To deny those of whom you're afraid
And provide peace of mind
Each day we're combined
With our partner who therein has stayed

This refers to how a lock is opened with a key, often daily.

At prominence ere the fall of Rome
We held the theaters, bridges and domes
In structures erected
We shan't be neglected
Lest one desires to topple our home

A keystone is placed at the top of an arch, and prevents the whole thing from falling down. it's surprisingly sturdy even though it doesn't quite look like it would be.

• Good effort, but not the intended solution. As always, I'll hint subtly with the next edit. Aug 13, 2015 at 19:24

Stanzas two and three are lock and key, respectively. (it refers to the keystone at the top of an arch, I'm guessing)

Stanza one, I'm assuming, is not "lightning" though I got a giggle out of an incidental reference to the webcomic "An Ordinary Princess."

Here's the reference that made me laugh. http://www.ordinary-princess.com/?comic=chapter-4-page-10

For a singular purpose we're made
To deny those of whom you're afraid
And provide peace of mind
Each day we're combined
With our partner who therein has stayed

This refers to how a lock is opened with a key, usually daily.

At prominence ere the fall of Rome
We held the theaters, bridges and domes
In structures erected
We shan't be neglected
Lest one desires to topple our home

A keystone is placed at the top of an arch, and prevents the whole thing from falling down. it's surprisingly sturdy even though it doesn't quite look like it would be.

• Stanza 1 might refer to arrows (from the forest, blotting out the sun and forcing 300 dudes to fight in the shade, supplies a road of bones in the sense that they're weapons of war that kill lots of things - or used to). I dunno, am I overthinking this? Arrow-Lock-Keystone doesn't seem to make sense, and I was thinking the three words would be connected. Aug 13, 2015 at 19:05
• the only idiom I can think of that links lock and key is something kept "under lock and key", but I don't see how under could be used.. maybe underworld/underground? skeletons? Aug 13, 2015 at 19:13
• Maybe some variation of Ents? Aug 13, 2015 at 19:15
• I think I might've gotten it. Answer coming soon Aug 13, 2015 at 19:16
• +1 for giving me the inspiration for my answer (even if it's wrong!) Aug 13, 2015 at 19:21

Scroll lock key (like the now useless one on keyboards)

Carved from a forest we lie
A road built of bone we supply
With great walls of black
We are known to attack
From the forest an echo replies

Scrolls can be made from paper which come from trees. The great walls of black is the text that is written on them. Magical scrolls can be used for spells and attacks.

For a singular purpose we're made
To deny those of whom you're afraid
And provide peace of mind
Each day we're combined
With our partner who therein has stayed

As per Kingrames; This refers to how a lock is opened with a key, often daily.

At prominence ere the fall of Rome
We held the theaters, bridges and domes
In structures erected
We shan't be neglected
Lest one desires to topple our home

As per Kingrames again: A keystone is placed at the top of an arch, and prevents the whole thing from falling down. it's surprisingly sturdy even though it doesn't quite look like it would be.

• I thought that the first part was referring to a pencil but scroll works too, and gets you a nice trifecta of words. Aug 14, 2015 at 17:21

I'll take a stab at it:

Could it be referring to:

Soldiers

As f" solved for Saturn
and Cain reasoned Stairs
While one word you seek
Three this riddle bears:

Carved from a forest we lie

A possible reference forest camouflage used by soldiers blend into the forest. Also that many times the soldiers can use the forest as cover and 'lie' waiting for their targets to pass through.

A road built of bone we supply

Soldiers can be used to create a secure path (road) 'built' from the bones of those that get in the way.

With great walls of black

A possible reference to a groups of soldiers shields (or nowadays tanks) that could be black.

We are known to attack

Soldiers are used in battles to attack the opponent.

From the forest an echo replies

In the medieval times you would be able to hear the soldiers shouts and battle cries when they are engaging.

For a singular purpose we're made

To deny those of whom you're afraid

A reference in stopping the enemy force by 'denying' them.

And provide peace of mind

They can eliminate the threat, allowing peace of mind knowing it is gone.

Each day we're combined

Soldiers are combined together to create a battalion when on duty.

With our partner who therein has stayed

While a soldier may go into battle, Often the spouse will remain at home for the family.

At prominence ere the fall of Rome

The Roman Empire was a defeated by and supplied vast amounts of soldiers

We held the theaters, bridges and domes

In urban battles (of WWII), many soldiers had to hold up in theaters and domes as well as protect bridges to maintain travel routes.

In structures erected
We shan't be neglected

Today we have many erected structures of previous soldiers and in memorial of their battles and losses. The help remind us to not neglect their sacrifices.

Lest one desires to topple our home

With a strong military (USA), people will not like to start fights them, or try to 'topple' their home.

• +1 for a complete answer, but not the one I intended. I'll add another hint. Aug 14, 2015 at 15:35
• @Roland I seem to find the 'Easter egg' answers in your riddles ;-P (Or I just stretch my answer to fit) Aug 14, 2015 at 15:39
• The more metaphorical the riddle, the more open-ended it becomes, so my apologies. If it helps, you do a superb job stretching your answers to fit, which is why I up-vote them anyways. Aug 14, 2015 at 15:55