episode
/ˈepɪsəʊd/noun
1- an event or a group of events occurring as part of a sequence; an incident or period considered in isolation（一系列事件中的）一个事件, 一组事件; 附带事件; （单独的）一段时间; 插曲：
one of the saddest episodes in the history of the army.
军队历史上最令人伤心的事件之一。
1.1
- each of the separate instalments into which a serialized story or radio or television programme is divided（连载小说中的）一节; （广播或电视连续剧的）一集。
1.2
- a finite period in which someone is affected by a specified illness（某疾病的）发作期：
acute psychotic episodes.
一次次急性精神病发作期。
1.3
- Music a passage containing distinct material or introducing a new subject【乐】插句, 插段, 插部。
1.4
- a section between two choric songs in Greek tragedy（希腊悲剧中）两段合唱之间的部分。
词源
late 17th cent. (denoting a section between two choric songs in Greek tragedy)： from Greek epeisodion, neuter of epeisodios 'coming in besides', from epi 'in addition' + eisodos 'entry' （from eis 'into' + hodos 'way'）.