for a while
prep. phr..prep. phr.. for a short period of time that is not exactly defined.
prep. phr.. an adverbial phrase indicating a non-specific, typically brief duration of time.
I am going to sit here for a while.
We waited for a while at the station, but the train was delayed by an hour.
The researchers observed the chemical reaction for a while before concluding that the temperature remained stable throughout the process.
usually functions as an adverbial of time at the end of a clause.
contrast with 'for a long time'; 'a while' is subjective but usually implies a duration long enough to be noticeable but short enough to be temporary.
I stayed there for awhile.I stayed there for a while.the two-word 'a while' is required after a preposition like 'for', whereas the single word 'awhile' is an adverb that already includes the meaning of 'for'.