stratification

n [U] arrangement in strata, etc; stratifying or being stratified 层次; 成层; 分层: social stratification 社会阶层.

strange, strangely, strangeness, stranger, strangle, stranglehold, strangler, strangulate, strangulation, strap, straphanger, strapless, strapped, strapping, strata, stratagem, strategic, strategically, strategist, strategy, stratify, stratoscope, stratosphere, stratum, straw, straw poll (also straw vote), straw-coloured, strawberry, strawberry-mark, stray, stray away from, streak, streaker, streaky, stream, stream of consciousness, streamline, streamlined, streamlining, street,