Ethnohistory is the study of ethnographic cultures and indigenous customs by examining historical records.
ˈɛθnəhˌɪstɚɹi ɪz ðə stˈʌdi ʌv ˌɛθnəɡɹˈæfɪk kˈʌltʃɚz ænd ɪndˈɪdʒənəs kˈʌstəmz baɪ ɛɡzˈæmɪnɪŋ hɪstˈɔːɹɪkəl ɹˈɛkɚdz.