This is the 7431st most frequent Chinese word.
號召
"號召" means "to call upon" or "to appeal."
The word "號召" is used here as a noun, meaning a call or appeal for action.
我們必須團結一致，響應號召。
We must unite and respond to the call.
Here "號召" functions as a verb, meaning to call on or urge to take action.
政府號召民眾參與環境保護活動。
The government calls on the people to participate in environmental protection activities.
In this sentence, "號召" is used as part of a compound noun "號召力," which refers to the ability to rally or attract support.