n.

1. 扩展；扩张；膨胀[U]
   The new factory is large, to allow room for expansion.

   新工厂很大，有地方可以扩展。

2. 扩大物[C]
   The suburbs are an expansion of cities.

   郊区是城市的延伸。

n.

1. the action or an instance of expanding.
   ▸the political strategy of extending a state's territory by encroaching on that of other nations.
2. the increase in the volume of fuel on combustion in the cylinder of an engine, or the piston stroke in which this occurs.