boomburb Syllabification: (boom·burb)Pronunciation: /ˈbo͞omˌbərb/Definition of boomburb noun US an outlying residential district of a city that is expanding rapidly:a sprawling boomburb of nearly 800,000 peopleOrigin: early 21st century: from boom2 + suburbboomburb in other Oxford dictionaries Definition of boomburb in the British & World English dictionary