拱顶石

• choke stone
• keystone
• key stone
• arch key
• crown block
• crown stone
• arch apex
• key

参考释义

拱顶石

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例句

1. 拱顶石位于拱顶的塞缝石
   The keystone in the crown of an arch.
2. 支拱板条专门用来在拱顶石放置好以前支撑拱的两边木架子
   A wooden frame built especially to support the sides of an arch until the keystone is positioned.