Watchword (noun)

A password or slogan used as a rallying cry, especially in military contexts.

Origin:

From the middle english word 'watchword' meaning 'watchful word'.

Examples:

1. The watchword of the army was 'duty, honor, country'.
2. The watchword of the political campaign was 'change for the better'.
3. The watchword of the protest movement was 'justice for all'.
4. The watchword of the environmental campaign was 'save the planet'.
5. The watchword of the social media movement was 'speak up, speak out.'.