subway  
noun [ C ] uk/ˈsʌb.weɪ/ us/ˈsʌb.weɪ/
  (RAILWAY)      
 A1 mainly US (UK usually underground)地铁;地铁交通 
a railway system in which electric trains travel through tunnels below ground
  We took the subway uptown to Yankee Stadium. 我们乘地铁到城外的扬基体育场去。 
 A guy gave me his seat on the subway. 地铁上一个男人把他的座位让给了我。 
 - More examples
 - Times Square is the nexus of the New York subway.
 - We looked on our map to find the nearest subway station.
 - I take the subway to work.
 - I left my bag on the subway.
 - I don't like to travel on the subway after dark.
 
  (PASSAGE)     
B2 UK行人地下道,行人隧道 
an underground passage that allows people on foot to cross a busy road