.Trashes folder

So don't worry!

In fact, when you put a file in the trash, your computer moves it to a special system folder.
On Windows, it's the RECYCLER folder.
On Mac OS, however, it's .Trashes (the . symbolizes a hidden file in UNIX language, and Trash means trash in English).
This folder is indeed the trash: the files you placed in the trash from the Mac are stored there until you delete them.
The fact that Windows displays it this way is simply because Windows and UNIX do not use the same standards for naming their system folders.

You can delete this folder without risk: it only affects UNIX OS (which will recreate a trash can when you plug your USB drive into a MAC/Linux), and the files placed in the trash from the Mac (which will then be deleted from your USB drive).

For Windows, there is this utility: www.trashes-mac.com

I had the same question as oderby, with a folder "Trashes" that was taking up all the memory on my mobile phone. I indeed connected my phone to a Mac.
Thank you Pwoned for this clear and precise answer!