四级 sìjí grade 4 Origin Definitions Defs Strokes Stroke Words Sentences Sents 四级士官 sìjíshìguān sergeant first class a senior non-commissioned officer rank, typically equivalent to sergeant first class第四级产业 dìsìjíchǎnyè quaternary industry the sector of the economy based on intellectual activities such as information technology, research and development, and education