1. Social justice is the keystone of their political program.
    社会公平是他们政治纲领的基本原则。

1. danci.911cha.com

1. 拱顶石：在<达芬奇密码>>中 拱顶石(Keystone)开始是被当作是揭开圣杯秘密的石头,其实其本意应为Key Stone,是指开启秘密的关键,就是后来出现的密码筒. 画作初成,便赢获世人的极度欢心. 法兰西王一片热忱,曾想拆下整面墙壁运回国内.

2. 关键：群落集合也许能被生境类型、物种移殖和定居,关键物种 关键( keystone)物种在群落中有一个重要的和不成比例的作用. 关键种可能是顶端的捕食者,像北方的海獭;然而这个词可以运用在任何一个物种上,只要这个物种被移去时会对群落结构造成重大影响.

3. 拱心石：从哈佛商学院教授马可.伊恩希提(Marco Iansiti)和顾问师洛.雷文(Roy Levien)借用拱心石(Keystone)与生态体系的譬喻,或许更能管窥Google成功的根本要素.

4. 拱石：在<达芬奇密码>>中拱*石(Keystone)开始是被当作是揭开圣杯秘密的石头,其实其本意应为Key Stone,是指开启秘密的关键,就是后来出现的密码筒.

1. 拱顶石
    A keystone is a stone at the top of an arch, which keeps the other stones in place by its weight and position.

keystone

2. （政策、体系或进程的）基础，主旨
    A keystone of a policy, system, or process is an important part of it, which is the basis for later developments.

keystone

    e.g. Keeping inflation low is the keystone of their economic policy.
           将通货膨胀率保持在较低水平是他们经济政策的主旨。

1. the central building block at the top of an arch or vault

    Synonym: keyheadstone

2. a central cohesive source of support and stability

    e.g. faith is his anchor
           the keystone of campaign reform was the ban on soft money
           he is the linchpin of this firm

    Synonym: anchormainstaybackbonelinchpinlynchpin