Starting from the top-left, going down and right:

* Yes
* No
* Question mark
* Exclamation point
* Arrow - can be tilted to point in any direction
* Time/wait - usually means "wait for a moment" when used without context, often because somebody wants to log out to change skins or because they want you to wait for someone else to catch up.
* Travel/go to - often accompanied by a symbol indicating where a person wants to go, or a question mark as a way of asking where you want to go. This usually means walk, not teleport/fast travel.
* Group (?) - this one rarely gets used.
* Follow - usually "follow me", but can also be used to indicate a group or other people.
* Friend - may be used to refer to you by the person you are traveling with, or in combination with an arrow or the time symbol to mean "friends this way" or "wait for friends". This is also the karma 3 symbol, but that meaning has no use in Meadow.
* Token plant - refers to the little black tentacle plants that grant you unlock tokens.
* Echo - refers to the "echo" spirits that grant you unlock tokens
* Shelter - can refer to actual shelters or used in combination with other symbols to indicate that you need to log off/go to bed. Shelters can also be used as fast travel points, so the shelter icon in combination with a symbol representing a region likely means that somebody wants to teleport to that region.
* Karma gate - used to indicate that somebody wants to go to another region via the gate.
* Hub - indicates that somebody wants to teleport to the region's hub (which, if you didn't know, you can do from the Esc menu). Useful if somebody gets stuck.
* Outskirts - indicates that somebody wants to teleport to Outskirts, which can be done in the same way as above. This is also the karma 5 symbol, but, again, that has no meaning in this context.
* Wander/wanderer - a rarely-used but useful symbol indicating that somebody is or wants to wander around or has no particular place they want to go.
* Antenna/connection - may be used in combination with the "no" symbol or the dead/dying emote to indicate that a person's game crashed (an unfortunately common problem with Meadow), or combined with the hello/goodbye waving emote to indicate that they need to log off. Can also refer to the Sky Islands region, or the Communications Array subregion specifically.
* Iterator - refers to Looks to the Moon, usually in combination with the friend or water symbol, or Five Pebbles, usually in combination with the machine symbol.
* Light/sound/pearl/ascension (?) - a pretty vague symbol that means a lot of things. Because it kind of looks like the karma 10 symbol, it can be used to refer to the Void Sea. I've also seen it used to refer to dev tools.
* Plants - can refer to the Farm Arrays. I've used it in combination with the movement and "no" symbols to indicate that I couldn't climb on vines as a lizard.
* Machine (?) - can refer to Industrial Complex, or combined with the iterator symbol to refer to Pebbles. I've also seen it combined with the antenna and "no" symbol to refer to a game crash.
* Pipes/tunnels- can be used to express any thoughts relating to pipes, such as the endless frustration cicadas feel just trying to enter and move through them. Can be used to tell someone to use the "unstuck" menu option which teleports them to the last pipe they used. May also refer to Drainage System.
* Water - water, obviously. Can refer to Shoreline and/or Looks to the Moon, whose subregion is connected to Shoreline.

Everyone uses them a little differently, so there's some ambiguity. You won't always be able to understand everyone.

My opinions:

I refer to LttM (Looks to the Moon) as Iterator and Water since I don't think of her as a friend. Does make since for people who do though.

I refer to 5P (Five Pebbles) as Iterator and Pearl because of all the pearls in his chamber. Now knowing that it also means ascension just makes even more sense. Technically someone could refer to 5P as a friend too.

In basic terms LttM is Iterator and Water and 5P is Iterator and Ascension. If you are friends with them than sure you can use Iterator and Friend.

Plants can refer to Outer Expanse in my opinion. I am pretty sure if you look at the plants area of the Rain World Wiki you can figure out what plants those actually are and match them with a region.

Now for my biggest complaint: PIPES = PIPE YARD. YES I AND OTHERS HAVE USED THIS AND IT MAKES PERFECT SENSE!!!

Originally posted by FishStrats:

My opinions:

I refer to LttM (Looks to the Moon) as Iterator and Water since I don't think of her as a friend. Does make since for people who do though.

I refer to 5P (Five Pebbles) as Iterator and Pearl because of all the pearls in his chamber. Now knowing that it also means ascension just makes even more sense. Technically someone could refer to 5P as a friend too.

In basic terms LttM is Iterator and Water and 5P is Iterator and Ascension. If you are friends with them than sure you can use Iterator and Friend.

Plants can refer to Outer Expanse in my opinion. I am pretty sure if you look at the plants area of the Rain World Wiki you can figure out what plants those actually are and match them with a region.

Now for my biggest complaint: PIPES = PIPE YARD. YES I AND OTHERS HAVE USED THIS AND IT MAKES PERFECT SENSE!!!

doesn't Rain Meadow not have support for downpour yet?

Originally posted by hi:

doesn't Rain Meadow not have support for downpour yet?

I've only just begun playing Downpour, so I don't know everything it includes, but I can tell you that Pipeyard, Metropolis, Submerged Superstructure, and Outer Wilds are all in Meadow.

Originally posted by Jimbo Jambo:

Originally posted by hi:

doesn't Rain Meadow not have support for downpour yet?

I've only just begun playing Downpour, so I don't know everything it includes, but I can tell you that Pipeyard, Metropolis, Submerged Superstructure, and Outer Wilds are all in Meadow.

Outer Expanse not Outer Wilds XD

Originally posted by hi:

Outer Expanse not Outer Wilds XD

That too.

How do you emote???