It is an essential definition because it attempts to get at the essential features of the concept - its necessary and sufficient conditions of application.

它是一个本质定义，因为它试图抓住这个概念的本质特点——即使用这个概念的必要条件和充分条件。

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In fact, that is essential to banking and it's kind of part of the -you might almost call it the definition of a bank.

事实上,这对银行业务是至关重要的,并且这是部分的...,几乎可以说这就是银行的定义

耶鲁公开课 - 金融市场课程节选

Digitally restored from high resolution film elements in perfect high-definition picture and perfect high-definition sound for the first time ever, Universal Classic Monsters: The Essential Collection brings together the very best of Universal's legendary monsters-imaginative and technically groundbreaking tales of terror that launched a uniquely American movie genre.

ENGADGET: Dracula, The Mummy and six other horror classics coming in a Blu-ray set October 2nd (video)