Secretary was a political title given to certain mid- or high-level governmental officials.
The title of secretary existed in the Federation. In the mid-24th century, M. Piller was the Secretary of Exploration. (TNG-R: "Chain of Command, Part II")
During the Cardassian Occupation of Bajor, Secretary Kubus Oak served as the special liaison between the Cardassian occupation forces and the Bajoran government. (DS9: "The Collaborator")
In 2365, Secretary Kushell was a representative of the Legation of Unity on Straleb. (TNG: "The Outrageous Okona")
In 2374, Romulan Senator Vreenak served as Secretary of the War Plans Council. (DS9: "In the Pale Moonlight")