Final answer:
The word 'avow' correctly fills in the blank as a 4-letter word meaning to declare openly. It is tied to the concept of making emphatic and explicit statements, which is pertinent to studying important historical declarations.
Step-by-step explanation:
The 4-letter word that means to declare openly is 'avow'. This term fits the given definition and none of the other options provided, such as 'Wave', 'Wait', or 'Wane', appropriately fill the blank with the correct meaning. To give you more context, the word 'avow' is somewhat similar to 'declaration' which is an emphatic and explicit statement. For instance, during Celebrate Freedom Week, students might learn about important declarations made throughout the history of the United States, such as when the founding fathers declared independence from Britain.
The other vocabulary terms provided, like 'abdicate' which means to give up power, 'absolve' which means to grant remission of a sin, 'allegiance' which indicates a commitment to a course of action, 'assent' which means to agree, and 'civil' which pertains to citizens, do not fit the definition provided for the blank in the question. Understanding these terms is crucial during Celebrate Freedom Week as they relate to the foundational concepts that underpin the values of the United States.