brass hat—(coll.)
1. a senior officer in the armed forces:
- For two hours in late January, the brass hats of the Pentagon cloistered themselves with President Clinton.
2. any important or influential person:
- The trouble was that he was a curate, and the brass hats of the Church look askance at curates who swat parishioners.
tin hat—a steel trench helmet:
- The trench hat, “the old tin hat,” is coming into quite extensive use as a means of head protection against small falls of rock in mines.