一人ひとり天てん下かalso: ひとりでんかひとりてんかMeanings1nounsole mastery; reigning supreme; unchallenged dominanceDescribes a situation where one person has complete control or influence, with no rivals. Often used in contexts like business, politics, or personal relationships.彼かれは会かい議ぎで一人ひとり天てん下かだった。He dominated the meeting unchallenged.