In material sciences and engineering the terms "asphalt" and "bitumen" are often used interchangeably and refer both to natural and manufactured forms of the substance, although there is regional variation as to which term is most common.
ɪn mətˈɪɹiəl sˈaɪənsᵻz ænd ˌɛndʒɪnˈɪɹɪŋ ðə tˈɜːmz "ˈæsfɔlt" ænd "bɪtˈuːmɛn" ɑːɹ ˈɔfən jˈuːzd ˌɪntɚtʃˈeɪndʒəbli ænd ɹᵻfˈɜː bˈoʊθ tə nˈætʃɚɹəl ænd mˌænjuːfˈæktʃɚd fˈɔːɹmz ʌvðə sˈʌbstəns, ɔːlðˈoʊ ðɛɹ ɪz ɹˈiːdʒənəl vˌɛɹɪˈeɪʃən æz tʊ wˌɪtʃ tˈɜːm ɪz mˈoʊst kˈɑːmən.