The standards for
Linguistics in American English are:
1. Use italics to cite a word, such as
word.
2. Use double quotes for a quotation, from another author. Chomsky said "Syntax is about colorless green ideas...."
3. Use single quotes for the meaning/gloss of a word/phrase/sentence:
palabra means 'word' in Spanish.
The standards
in general in American English are:
1. Use double quotes to indicate non-literal material including words you are referring to, like "word".
2. Use double quotes for quotations.
3. There is no standard use for single quotes (except quotations within quotations).
4. There is no standard use for italics except sometimes emphasis.
In my notes I often use double quotations marks because they are more visible (and, of course, I cannot use italics), but I wonder how to mark definitions.
Double quotes is normal in this situation.
1) The adverb “ibid.” means ‘in the same place’.
2) The adverb “ibid.” means “in the same place”.
Unless you are
doing linguistics in reference to abbreviations (like talking about etymologies and usage in a corpus), then you should use option (2), because that's how we would normally refer to such things in an explanation in normal text.
However, that way of phrasing it seems awkward to me, and informal. I'd try to rephrase some other way to avoid the problem.