石炭系
shí​tàn​xì

Carboniferous system

shí​tàn​xì Carboniferous system
  1. 石炭 shí​tàn
    coal
    (archaic) coal; anthracite; an ancient name for 煤 méi
  2. 系 xì
    system (geology)
    (geology) a chronostratigraphic unit of rocks formed during a period of geological time, ranking below an erathem and above a series

shí​tàn​xì coal measures
  1. 石炭 shí​tàn
    coal
    (archaic) coal; anthracite; an ancient name for 煤 méi
  2. 系 xì nounnumeral
    system (general)
    (bound form) a group of related things that form a whole; series; family