Idaho UK /ˈaɪdəhəʊ/US /ˈaɪdəˌhoʊ/ noun2 •A state in the western United States. Capital and largest city: Boise.Oregon’s uptick in marijuana sales along the Idaho border doesn’t necessarily mean that it’s all Idahoans who are lighting up, Lehner said. — 2020 •In full Idaho potato: a variety of potato grown in Idaho, especially the Russet Burbank. formsIdahos