engine room

1. N-COUNT On a boat or a ship, the engine room is the place where the engines are. (轮船的)轮机舱

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. (组织、机构等)最重要的部分; 最具影响力的部分[oft 'the' N 'of' n]

These firms are regarded as the engine room of the economy. 这些公司据信对经济有重大影响力。