awhile VS. a while

As a noun phrase after a preposition such as after, for, in, within, one should use two words, a while. In that case, it means 'a short or moderate time'. If one is using the term adverbially, it should be spelled as one word, awhile, which means 'for a short time'. Examples of each are: I will stay for a while at the party. He napped for a while. / She stayed awhile at the party. I napped awhile on the couch. This topic is a fine point of grammar and for many uses only writing it will distinguish which syntactic structure one should use