階かい層そうかいそうCommon wordJLPTN1Freq.FrequencyTop 20,000Meanings1nounhierarchy; stratum; layer; level; classRefers to a structured layer or rank within a system, such as social classes, organizational levels, or geological strata. Often used in technical and formal contexts.社しゃ会かいの階かい層そうについて研けん究きゅうしている。I am researching social strata.