auエーユーFreq.FrequencyTop 5,000じ字FuriganaMeanings1nounau (Japanese mobile phone operator)company nameA major Japanese mobile phone brand operated by KDDI. Often used in contexts discussing carriers, plans, or devices.auの新しん料りょう金きんプランに変へん更こうした。I switched to au's new rate plan.彼かれはauのスマートフォンを使つかっている。He uses an au smartphone.