Final answer:
The term "unite" refers to the action of joining together for a common purpose, with "merge" being a synonym. It is often used in contexts where collective effort is needed for a larger goal or to overcome an adversary.
Step-by-step explanation:
The word "unite" means to come together or join for a common purpose or action, especially to become one or work together harmoniously. A synonym for "unite" could be "merge", which also suggests combining or joining together into a single entity. Historical and contemporary contexts provide examples where unity is essential, such as countries or groups coming together by the necessity to defeat common enemies or promoting a sense of national identity during times of conflict.