1. 插曲;事件;时期
    You can refer to an event or a short period of time as an episode if you want to suggest that it is important or unusual, or has some particular quality.

    e.g. This episode is bound to be a deep embarrassment for Washington...
           这一事件肯定会让华盛顿非常难堪。
    e.g. Unfortunately it was a rather sordid episode of my life.
           不幸的是，这是我人生中非常不光彩的一段经历。

2. （广播剧或电视剧的）一集;（杂志连载故事的）一节
    An episode of something such as a series on radio or television or a story in a magazine is one of the separate parts in which it is broadcast or published.

    e.g. The final episode will be shown next Sunday.
           下周日将播出最后一集。

3. 患病期;（病症的）发作期
    An episode of an illness is short period in which a person who suffers from it is affected by it particularly badly.

    e.g. ...people who'd suffered a third episode of depression in two years...
           两年内忧郁症3次发作的人
    e.g. The new drug lessens the severity of pneumonia episodes.
           新药减轻了肺炎发作时的痛苦。