終始

1. Origins, structure, and basic meaning

• Structure: 終始 combines characters for the end and the beginning to express the span from start to finish.
• Basic usage: It describes a state maintained throughout an event, such as remaining silent through a meeting or controlling a game throughout.

2. Common pitfalls and similar expressions

• Difference from 始終
  • 終始 emphasizes the entire span of one event. 始終 can express that span too, but can also describe an action recurring all the time or frequently.
• The evaluative use of 終始する
  • 説明に終始する limits the activity to doing nothing beyond explaining. It differs from 説明が終わる, which simply says that the explanation ends.