To invade a country means to enter it by force with an army.
双语例句
例：
In autumn 1944 the Allies invaded the Italian mainland at Anzio and Salerno.
1944年秋，盟军从安齐奥和萨莱诺侵入意大利本土。
2.?[T 及物动词] 拥入
If you say that people or animals invade a place, you mean that they enter it in large numbers, often in a way that is unpleasant or difficult to deal with.
双语例句
例：
People invaded the streets in victory processions almost throughout the day.