apropos of somethingused to introduce a new subject that is related to something just mentioned
[TahlilGaran] Dictionary of Contemporary English ▲
apropos of prep.,
formal In connection with; on the subject of, about; concerning.
Apropos of higher tuition, Mr. Black told the boy about the educational loans that banks are offering. Mr. White went to see Mr. Richards apropos of buying a car. [TahlilGaran] English Idioms Dictionary ▲