To be specific, a student of mine wrote the sentence "便所 means stool in Japanese" and that didn't seem right to me. "便所 is stool in Japanese" seemed - again, intuitively - right to me. We had a discussion about it, and we stumbled on the topic of untranslatable words and whether or not, when attempting to explain or define the word in another language, one should use "X means Y" or "X is Y".
As an example, the word "頑張る" has many equivalents in English, depending on the context, such as "good luck" or "do your best" or "break a leg". When attempting to explain the definition of such a word in English, should one say "頑張る is to..." or "頑張る means to..."?