IdahoPronunciation: /ˈʌɪdəhəʊ/Definition of Idaho a state of the north-western US, bordering on British Columbia to the north and containing part of the Rocky Mountains; population 1,523,816 (est. 2008); capital, Boise. It became the 43rd state of the US in 1890. Derivatives Idahoan noun & adjective Idaho in other Oxford dictionaries Definition of Idaho in the US English dictionary
