the top brass

The person or people with the most authority, power, or influence in a group or organization. When I was the top brass of the business, I used to charge the most outrageous things to the company credit card. You'll only get a truthful answer if you manage to talk to the top brass.

the highest leader(s); the boss(es). (Originally military.) The top brass turned thumbs down on the proposal. You'll have to check it out with the top brass. She'll be home around five.

see under brass hat.

The highest-ranking officials or executives in an organization. The expression is generally thought to come from the late-nineteenth-century British army, when senior officers had gold oak leaves decorating the brim of their caps. John Ciardi, however, proposed another etymology, from the cocked hat worn by French officers in Napoleon’s time, which was folded and carried under the arm (in French, chapeaux à bras) while indoors; Ciardi believed the British changed bras to brass, and referred to officers as brass hats. By World War II both that term and top brass were in common use and afterward were transferred to peacetime officialdom as well. Thus, “The top police brass spreads out a hot carpet for the local cops” (Philadelphia Bulletin, 1949).