keystone
/ˈkiːstəʊn/ (bre, ipa) · /ˈkiːstəʊn/ (ame, ipa) · /ˈkē-ˌstōn/ (ame, mw)
keystone — 名詞
- keystonesingular
- keystonesplural
1. the wedge-shaped block placed at the very top of a stone arch, which locks every
拱心石
拱門最頂端的楔形石塊，固定其他石塊
the wedge-shaped block placed at the very top of a stone arch, which locks every other block tightly into place.
Gabriel pointed up at the chapel arch and named the carved keystone above the door.
Gabriel 指向小教堂的拱門，向大家介紹門上方那塊雕花的拱心石。
keystone of an arch (literal architectural use)
Without its keystone, the old Roman arch would crumble within minutes under its own weight.
如果少了拱心石，那座古老的羅馬拱門幾分鐘內就會在自身重量下崩塌。
without its keystone + structural consequence
The mason cut the keystone last and slid it into the centre of the bridge arch.
石匠最後才切出拱心石，再把它嵌進橋拱的正中央。
Tourists photograph the carved lion's face on the keystone above the cathedral's main entrance.
遊客紛紛拍下大教堂正門上方那塊拱心石上雕的獅子臉。
Engineers warn that one cracked keystone can bring the entire arch down on the road below.
工程師警告說，只要一塊拱心石出現裂縫，整座拱門就可能塌到下方的馬路上。
文法句型
the keystone of [arch/vault]
用法筆記
Only sense that takes a physical preposition like 'above' or 'on'; the second sense is always followed by 'of' plus an abstract noun (a plan, an argument, a policy).
常見錯誤
2. the single element of a plan, argument, or system that holds everything else tog
關鍵基石
整個計畫或論點賴以成立的最關鍵部分
the single element of a plan, argument, or system that holds everything else together — remove it and the whole structure falls apart.
Affordable childcare became the keystone of the candidate's campaign for working families.
平價托育服務成了這位候選人爭取雙薪家庭支持的核心政見。
the keystone of [a campaign / policy / plan]
Amira argued that mutual trust is the keystone of every successful long-term business partnership.
Amira 主張，互信是每一段成功長期合作關係最關鍵的基石。
X is the keystone of Y (defining the central support)
Once the prosecution's main witness changed her story, the keystone of the case quietly fell away.
檢方的主要證人一改口，整起案子的關鍵基石就這樣悄悄崩落。
For Defne, weekly family dinners are the keystone that keeps her three grown children close.
對 Defne 來說，每週的家庭聚餐是把三個成年子女維繫在一起的核心。
Reliable rainfall is the keystone of farming in this valley; one dry summer ruins the whole harvest.
穩定的降雨是這座山谷農業最關鍵的基石；一個乾旱的夏天就足以毀掉整年收成。
- cornerstone
near-synonym; cornerstone is the foundation you build up from, keystone is the piece at the top that locks everything else
- linchpin
more informal; emphasises that removing this part causes immediate collapse
- lynchpin
British spelling variant of linchpin; same meaning
文法句型
the keystone of [plan/argument/policy]
用法筆記
Almost always 'the keystone of X' with a singular noun phrase; saying 'a keystone' weakens the meaning because by definition there is only one central support. Distinguish from sense 1 by the abstract object — plans, arguments, policies, partnerships, never physical stones.