a favour or advantage granted in return for something

the pardon was a quid pro quo for their help in releasing hostages

a writ or legal action requiring a person to show by what warrant an office or franchise is held, claimed, or exercised

rigorous quo warranto proceedings

the existing state of affairs, especially regarding social or political issues

they have a vested interest in maintaining the status quo

the previously existing state of affairs

a reversion to the status quo ante

the earliest possible date for something

the evidence clearly establishes a terminus a quo of 1602