engine room

1. N-COUNT On a boat or a ship, the engine room is the place where the engines are. (輪船的)輪機艙

2. N-COUNT If you refer to something as the engine room of an organization or institution, you mean it is the most important or influential part of that organization or institution. (組織、機搆等)最重要的部分; 最具影響力的部分[oft 'the' N 'of' n]

These firms are regarded as the engine room of the economy. 這些公司據信對經濟有重大影響力。