Hidden folder without a dot at the start

On any unix machine, Mac included, files and folders with dots at the start are normally invisible. However, it seems that the Mac has it's own type of hidden folder.

If I enable showing hidden files in Finder (defaults write com.apple.Finder AppleShowAllFiles YES), there are 70 dotfiles in my home directory. However, there are two hidden folder without dots: Trash and Library. In the root directory, there are several (lost+found, bin, cores, etc…).

Is it possible to make one of these folders that is hidden in Finder while keeping it's path the same (AKA not adding a dot)? I use a utility that needs a ~/tmp folder, and I'd love to hide it in finder.

You can use chflags

To hide a file from Finder

chflags hidden /Path/To/File

To unhide:

chflags nohidden /Path/To/File