Folder or Directory?

Well, I have a (probably bad) habit of using word folder (and it's Czech translation) when talking about computer directories, and sometimes I get corrected by the listener. So I wondered which is the correct usage - should I use folder, directory, or is either fine? I must also confess that the Czech equivalents for folder (složka) and directory (adresář) are causing me the same pain - I don't know which one is the correct. So I picked up my English dictionary (I don't have a Czech one, therefore I picked the English one) and looked up the words:

folder noun 1 a folded cover or large envelope for holding or filling loose papers. 2 a computer directory containing a number of files. 3 NAmer a leaflet or brochure

directory noun 1 an alphabetical or classified list, e.g. of names, addresses, telephone numbers, etc. 2 on a computer, a list of the files contained in a disk. 3 formerly, a book or collection of directions or rules, esp concerning forms of worship.

Now, the Czech counterpart for folder has more or less the same meaning (etymologicaly) as the first meaning of folder, and the counterpart for directory means basically a list (sorted) of addresses - it's even created from the word address, in Czech adresa.

So if I look on the original meanings (or in case of directory its current meaning outside of the computer world) of the words both in Czech and in English, I come to a conclusion that usage of folder is more meaningful than usage of directory, yet in linux it seems directory is the word of choice. I guess I am as confused as in the begining...

Any thoughts on this matter?