serve

When you serve food or drink, you give it to somebody to eat or drink, especially as a host.

Example: Shall I serve your drinks first?

If something serves (as something), it used or useful for a certain purpose.

Example: This cup can serve as a holder for my paintbrushes.

When you serve (as something), you work.

Example: John served in the army.

If you serve time in prison, you stay there because you are a criminal.

If you serve, in a game like tennis, you begin play by sending something like a ball over a net.