This question and this question are not really duplicates, however they are similar. I gave a pretty good answer to one, but that answer actually fits even better on the other question. Is it bad form to copy my answer completely over from one to the other?
On other SE sites (I have English.SE in mind), if questions attract similar answers, then they are considered duplicates.
For example, questions "what does the term X mean?" and "how has the meaning of the term X changed over the years?" are not really the same. But since they are likely to attract the same answers, they are likely to be merged into 1 question by a moderator or one of them can be closed as a duplicate of another.