What does SAO stand for?
Salvation Army Officer.
Salvation Army Colonel Arthur S Arnott was a relative of the firm W. Arnott, the now famous Australian biscuit manufacturers.
Launched in the early 1900s, the biscuit is said to have been named SAO after the Colonel for his work as a Salvation Army Officer. For 50 years, Colonel Arnott was a specialist in the work of young people.