I know we have done this before but…
Distinguishing “awhile/a while” need not continue to be an issue. As one word, “awhile” is an adverb; as two words, “a while” is a noun. Each means “for an indefinite period of time.”
There are some contexts that demand that it be two words, that is, that call for a noun.
…in a while
…for a while
…a while ago
…a while back
One of the things nouns can do in English is to function as what is called an “adverbial objective.” This is a noun that answers an adverb question. The adverb questions are “When?” “Where?” “Why?” and “How?” Consider the underlined words in these examples:
…I will be in late tomorrow. [“Tomorrow” answers the question “When?”] …The job took hours. [“Hours” answers the question “How long?”] …He spent thousands on that apartment. [“Thousands” answers “How much?”]
In the sentence “We were together awhile/a while,” our word is adverbial in nature. So is it one word or two? The answer is that it could be one word as an adverb and that it could be two words as a noun that is functioning as an adverbial objective. Since it has to be two words in some contexts and COULD BE two words in others, the moral of the story is to use it as two words all the time. Take it out of your dictionary as one word – one small step in the “Is this one word or two? I never know what to do with this” solved.