中国网站品牌栏目（频道）
My comments:
Literally, coin of the realm is the legal money of a particular country. The British, some of them that is, used to refer to the United Kingdom as The Realm.
Figuratively speaking, if something is described as “coin of the realm”, then it is highly valued – as if it were money in a particular realm (area, sphere).
In the above example, hard economic times in the 1970s led businesses to paying more attention to cost, hence the idea cost efficiency began to gain currency, i.e. to be more and more accepted.
In fact, it became “the coin of the realm”, or in other words the order of the day.
Related stories:
Spotting and eliminating "pork"
本文仅代表作者本人观点，与本网立场无关。欢迎大家讨论学术问题，尊重他人，禁止人身攻击和发布一切违反国家现行法律法规的内容。
About the author:
Zhang Xin（张欣） has been with China Daily since 1988, when he graduated from Beijing Foreign Studies University. Write him at: zhangxin@chinadaily.com.cn, or raise a question for potential use in a future column.
With the 1970’s came the Arab oil embargo and difficult economic times. Financial accountability became central to marketing strategy. Consequently, marketers began to pay more attention to cost efficiency and cost per Gross Rating Point (GRP) became the coin of the realm.
