Trash in WordPress refers to a temporary storage area where deleted posts, pages, comments, and other content are kept before they are permanently deleted. When you delete content on your WordPress website, it is moved to the trash rather than being immediately deleted.
Obviously, you have separate trash folder for each post types.
Items in the trash can be restored if you change your mind and want to recover them. This can be useful if you accidentally deleted something or if you want to review content before permanently deleting it.
By default, items in the trash are automatically deleted after 30 days. If you want to permanently delete items in the trash before the 30-day period, you can manually empty the trash.