rundown 既真正解釋

1. You are correct that from the dictionary run down = 概要或緊縮
2. On the TV (actually for all programs such as a show, a concert or even an activity in the school), people use run down to represent the 概要.
This is originated from the meaning of 概要. When we do a show we have to put down all the details such as what time to start, how long each performance will be, how long is the advertisement time. So the phrase run down became the meaning of 流程, which is equals to details.

Run-down:
a detailed report:
Here's a run-down on/of the activities of our ten biggest competitors.

1. 減少
2. 概要
Give me the rundown on the election results.
向我扼要概述一下選舉結果。
3. 逐條核對(或檢查)