The word "炽盛" is formed by combining the character "炽", which consists of the fire radical (火) for meaning and the component "只" for phonetic suggestion, denoting blazing intensity, with the character "盛", which consists of the container radical (皿) for meaning and the component "成" for phonetic and semantic contribution, denoting abundance or prosperity. Together, they create a compound where "炽" modifies "盛" to express a state of intense flourishing or fervent vitality.