One way to hold this title is to picture a government as a row of desks, each desk piled with the papers of one part of public life: roads on this one, schools on that one, dealings with other countries on the next. Every desk has one person who is trusted with those papers and who must stand up and answer for them in public. Secretary can be thought of as that trusted person, and of state as the note saying the desk belongs to government rather than to a company. Which desk, and at which level of government, is what the words around the title tell you.