But seriously, I do often use that word when describing a sound that reminds me of acoustic or physical resonances.
I think it can be questionable when trying to sell something but it has some validity for trying to describe certain kind of timbres and tones.
IMO it’s pretty much as usable as a term as “hollow”, “metallic” or “synthetic”.
Organic means FM
Or sounds like a B3
I don’t use these words but I guess the line between acoustic and organic is simply how realistic you wanna go.
Let’s continue with the analog hi-hat example. For it to sound more “acoustic”, all these steps will help:
Now you can also change the following:
8. change the pitch with each stroke
9. change the reverb amount with each stroke
all these parameters if applied very subtly will make your hi-hat sound more “realistic”/“acoustic”. Now go a bit crazy in the amount of modulation on 2 or 3 parameters (pitch, attack, noise type, reverb) and you’ll switch from the “acoustic” world to the “organic” world.
There are drum machines that do not sound like a real drum at all but feel “organic” because they have all these non-linearities in their sound engine that makes them sound “alive” = “organic”. Most often than not, analog engines will create these non-linearities (even though some of them are digitally controlled so they implement drifting like in the A4 or a “vintage knob” like in some Sequential synths to add a bit more mojo).
Organic can mean acoustic but not necessarily.
Organic certainly means (unpredictable) “movements”, that’s for sure.
But it’s just best to trust our ears.
Succulents.
I find for example that the Nord Drum (probably all of them) utilizes some of this brilliantly with its dynamic envelopes that combine decay modulation with velocity, gives me a feeling of organic.
I find that the specific way sounds decay or release is relevant as well, even when these aren’t modulated.
I wish David Cronenberg collabs with Elektron sound engineers to realize the ultimate organic drum machine that connect thru neural connectors and instantly recognise the beat I have in mind 
“denoting or characterised by a harmonious relationship between the elements of a whole”
Tiny imperfections coming from the oscillators, filters or somewhere else in the circuitry. Or imitation of via clever coding.
Interesting interpretation. I looked up the etymology of “acoustic” and in modern English the term acoustic to describe an instrument only came into use after the invention of the electric guitar. The older modern use is to describe the acoustics of a building. Buildings and acoustic instruments are in essence inanimate. And the process of striking a chord is mechanical, not something that organically emerges, but the result of will and technique. OTOH, the sound of a tree being struck by lightening and falling down I’d maybe describe as organic as in the sound emerges from a natural process, indeed an unpredictable movement of nature.
The process of striking a chord is usually initiated by an organism called ‘human’, though ? And that means, depending on the particular human, it will not be exactly mechanically repeatable, but rather, subject to variations.
Well, I reckon describing this as “animating” a static sound is more accurate. But obviously there’s no “right” explanation or answer.
Just take any performance of an acoustic instrument that has repeated notes, and recreate those repeated notes with one shot samples (made from the same performance). Comparing the original with that, you’ll hear the difference only.
A main thing for me is, especially striking to hear with drums, that you hear a play of overtones, which makes it sound alive. While with the sample, you hear one configuration of overtones and experience fatigue.
It’s also about subtle movement and changes in the harmonics of the notes
Interesting point. Makes me wonder: A woodpecker tapping into a tree, is it an organic or mechanical sound? It is mechanical in so far as the noise is the result of the bird exercising will and its bio mechanic facilities to achieve a goal. OTOH, the intent is not to produce sound, but to make a hole in the tree, thus the sound could be described as organic as in coming from nature.
Following this logic, singing vs farting, burping snoring etc. The former is mechanical, the latter organic.
It’s organic, but so precise that it comes close to “sound” mechanic. But here again, listening to a one-shot sample made of the same woodpecker recording repeated at that speed and comparing that will reveal the difference.
Does it sound like you are in a forest or in a padded room?
So maybe headroom is a factor? With obstacles filtering (imperfections, more relatable to nature)?
Sounding warm/woody seems to be a common theme for sound sources but that doesn’t have to include imperfections each time (although that helps).
A cheap acoustic vs a decent one is usually a great example.
Organic rhythm is a different story. This is where imperfections to pitch/volume/timing are more important. It helps to have good sources of sound but I guess that applies to everything heh 
Randomness (maybe more on the slight side) feels organic because the world is unpredictable?
This is quite philosophical isn’t it
Just look at your succulents they will know and respond accordinly.
Does the meaning change if we replace organic with animated?
If ifs and buts were apples and nuts we’d munch our lives away 
Good question. I’d say a beat is already playing wether it’s perfect or not? Hmm…
Let’s look at modern anime vs say older Studio Ghibli where everything was hand drawn frame by frame.
This is where the slight imperfections make one feel organic vs not (although modern filters are pretty close)
But I also understand that animated can mean a few things. So it’s a good candidate!