Is there a word or concise phrase for "alternative name for something"? (but not pseudonym or alias)

Question
Is there a word or concise phrase for "alternative name for something" which doesn't have the associated negative connotation that pseudonym and alias have? It has to be short so as to fit within a web link.

The negative connotation which I feel is invoked with pseudonym and alias is something along the lines of "hiding behind a false identity." Alias is probably the less negative of the two but if there is a better word or concise phrase altogether I would much prefer to use that. Thanks for your help.

Some contextual info as requested
On the website teachers are able to create alternative names for the subject they teach. For example, the default selection is Mathematics but they may want to create an alternative name of Maths, RS instead of Religious Studies and so forth.

Solution 1:

You might try one of:

• sobriquet
• moniker
• appellation

Or another synonym (though I'd avoid epithet, because it's accumulated negative connotations).

Solution 2:

On the basis of your additional information, I suggest these possibilities:

• Other name

• Abbr. name [for 'Abbreviated name']

• Short name

• Also known as

• Also called