The word rally has several related meanings:

1. To come together for a common purpose, especially when facing difficulty. When a sports team is losing badly but fights back to tie the game, they rally. When a community rallies around a family after a house fire, neighbors bring food, clothes, and help. The word suggests gathering strength through unity and determination.
2. A large public meeting where people gather to support a cause or hear speakers. A political rally might draw thousands of people to hear a candidate speak. A pep rally before a big game brings students together to cheer for their team.
3. In tennis and similar sports, a rally is the back-and-forth exchange of shots between players. A long rally might involve twenty or thirty hits before someone scores. Players rally until one makes a mistake or hits a winner.
4. To recover strength or spirits after weakness or decline. When someone rallies after being sick, they start feeling better and regaining energy. Stock prices rally when they rise after falling.

The core idea connects all these meanings: gathering force, whether that's people coming together, spirits lifting, or energy returning. To rally is to mobilize strength when it matters most.