noun
top brass; upper echelon; higher-ups; top management
Refers to the senior leadership or decision-making level within a company, government, or other organization. Often used in contexts of policy, decisions, or internal dynamics.
その決定は上層部で行われた。
The decision was made by the top brass.
上層部の意向が現場に伝わっていない。
The intentions of the higher-ups aren't reaching the front lines.
経営陣 is the management team, typically in a corporate context, whereas 上層部 can be used in any organization including government or military.
Compound of 上層 (じょうそう, 'upper layer') + 部 (ぶ, 'section, division'). The term straightforwardly denotes the upper section or stratum of an organization.