What is "the ground"?

Question

The spell Maximilian's Earthen Grasp describes compacted soil rising from the ground (Elemental Evil Player's Companion, p. 20):

You choose a 5-foot-square unoccupied space on the ground that you can see within range. A Medium hand made from compacted soil rises there and reaches for one creature you can see within 5 feet of it.

This could be interpreted as meaning that compacted soil needs to come from "actual" ground containing dirt. (And this is how some folks in my one gaming group interpreted it.)

However, other spells, such as Tenser's Floating Disk, refer to "the ground," where that could be any solid surface beneath you, be it the cave floor, a building's floor, or the actual ground - or at least that was the general consensus in this question about D&D 4e: What counts as ground for Tenser's Floating Disk?

The spell Move Earth (PH, p. 263) which specifically affects soil, uses the terms "terrain" and "dirt" - not "ground."

Does "the ground" simply mean whatever solid surface the characters/monsters are standing on?

Answer 1

The Mold Earth Cantrip

Funny enough, I've actually had a similar discussion with my 5th Edition D&D group. My search for the difference between dirt and ground led me to this question, which led me to the look at the wording of the Mold Earth cantrip:

You choose a portion of dirt or stone that you can see within range and that fits within a 5-foot cube. You manipulate it in one of the following ways:

• If you target an area of loose earth, you can instantaneously excavate it, move it along the ground...

• You cause shapes, colors, or both to appear on the dirt or stone...

• If the dirt or stone you target is on the ground, you cause it to become difficult terrain. Alternatively, you can cause the ground to become normal terrain if it is already difficult terrain...

• 5th edition D&D, Elemental Evil: Player's Companion (pg. 21)

Interpreting the Wording of the Mold Earth Cantrip

1. "If you target an area of loose earth, you can instantaneously excavate it, move it along the ground ..."

I believe loose earth means "broken up" earth: the substance of the land surface; soil (soil, clay, loam, etc.) - from the 2nd definition of "earth" provided by Google.

Here, loose earth describes the substance being moved and ground describes the terrain across which it is being moved: the he terms are not interchangeable. We may extrapolate that "ground" refers broadly to "any solid surface on the planet", including stone or ice not covered by soil, per the Google's definition of "ground".

2. "If the dirt or stone you target is on the ground, you cause it to become difficult terrain. Alternatively, you can cause the ground to become normal terrain if it is already difficult terrain."

Here, a distinction is made between "dirt" / "stone" and "ground". The use of the conjunction if indicates that the dirt or stone is not necessarily one and the same as the ground. This supports my claim that, according to the 5th edition rules of D&D, the term "ground" is not interchangeable with "loose earth", "soil", "dirt", "stone", and so on.

Relationship of Terrain and Movement

Lastly, I think it is important to clarify the definition of difficult terrain in 5th edition D&D:

... adventurers often face dense forests, deep swamps, rubble-filled ruins, steep mountains, and ice-covered ground - all considered difficult terrain.

• 5th edition D&D, Player's Handbook (pg. 182)

In this excerpt and in the Mold Earth cantrip's description, the term "ground" is used in relation to the terrain. Here, ground very clearly is used to describe the solid surface while the term terrain is used when discussing movement on that ground.

A Counter Argument: The Move Earth Spell

... Because the terrain's transformation occurs slowly, creatures in the area can't usually be trapped or injured by the ground's movement.

• 5th edition D&D, Player's Handbook (pg. 263)

Here, "terrain" and "ground" are used interchangeably to describe a solid surface (where the terrain's transformation causes the ground's movement). Regardless, this doesn't confuse the concept of ground... I only bring this up to remind you that, depending on the context, "terrain" may refer to 1) describe the solid surface or 2) discuss movement upon that surface.

My Final Answer

Pulling it all together...

Does the ground simply mean whatever solid surface the characters and monsters are standing on?

Yes. The ground is a surface that could conceivably harbor some object on it. When discussing motion on that surface (of characters, monsters, bookshelves, etc.), most text in 5th Edition D&D rule-books uses "terrain". Sometimes, "terrain" is used instead of "ground" (but not the other way around).

Again... ground refers broadly to any solid continuous, contiguous surface on the planet. Terrain refers broadly to any solid continuous, contiguous surface that the characters or monsters move on.

Terms like dirt, stone, and ice are very specific and can only be interpreted as dirt and stone, respectively - they are not interchangeable. According to Jeremy Crawford's tweet, dirt and loose earth are fairly interchangeable terms:

Q: What's loose earth for the Mold Earth cantrip? Not stone, or a more specific type of dirt structure?

A: Think dirt, not stone.

• Tweet from @JeremyECrawford

As a GM, I'd clearly define "dirt" separately/distinctly from "soil", (loose earth and dirt can be interchangeable). Dirt isn't necessarily arable, while soil is necessarily arable.

As a note, I have heard people say "fertile soil" (never "fertile dirt"). As @GreySage commented, this may mean that soil may be "infertile". I'd imagine that in such a case, you'd simply refer to it as dirt, sand, etc. To be on the safe side, take care as a GM to specify the ground's soil type when needed so that the ground is "well-defined" for players to choose spells and make role-playing decisions.

For reference:

Soil: the upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles.

Dirt: earth used to make a surface for a road, floor, or other area of ground.

• Definitions from Google

Answer 2

D&D is written in English and unless a term is specifically defined it just takes its normal English definition(s). Googling "ground definition" gave:

the solid surface of the earth. "he lay on the ground"

So, yes, it means the solid earth under their feet be it made of soil, rock or tapioca pudding.

Answer 3

This depends on the definition of "the ground". 5e uses typical terms in English, unless they are they are specifically given other meaning as game terms of art. In English, "the ground" is a relative term, since what is clearly ground to a giant might not be ground to a tiny bug. I would instead say ground is specifically anything which, as of very recently, counted as a hex or square on which a Medium creature could stand on in the presence of gravity (including with Spider Climb whether active or not). The ground would probably include any detritus which would make it be considered Difficult Terrain.

For example, the spell Arcane Gate refers to "the ground". In that case:

• The rubble staircase of a flying ruined castle would be 'ground' (even though it isn't perfectly flat, it is equivalent to a hill; it has protrusions because it has a bunch of stones; it is wood and not earth and that is fine).
• However furniture and desks (especially if they have function are are searchable) would not count since they are separate items (unless the GM is treating them as Difficult Terrain).
• Vehicles are a bit ambiguous, but any vehicle which is treated as a hex/square you can stand on (e.g. not horses, ambiguously chariots) should probably count, like giving the command word to a Folding Boat then (because you are >500ft or somesuch) take an action to summon an Arcane Gate on it should be fine.
• It is ambiguous what happens to the portal if the ground suddenly disappears (if it is destroyed suddenly by the DM in some way in an epic destructive event); obviously the DM may then adjudicate.

Consequently in the Arcane Gate example, a portal may be at weird angles, and almost entirely flat or even sticking into the ground, if there exists sufficiently large rubble (e.g. bricks, small boulders, etc.) to change the normal surface over a few inches. Or just stick it on a wall (but not a curtain, since it's too flimsy to hypothetically stand on). Otherwise in a flat hallway, the portal would be sticking straight up.