1
a casement window
casement 常作定语修饰 window，表示平开窗。
The bedroom has a casement window that opens outward.
这间卧室有一扇向外打开的平开窗。
窗扇；平开窗扇
先理解核心含义，再看它在真实句子里的用法。
窗扇；平开窗扇
a window sash that is hinged on one side
The bedroom has a casement window that opens outward.
这间卧室有一扇向外打开的平开窗。
铰接在侧面的窗扇。
A window sash that is hinged on the side.
带有这种窗扇的窗户；平开窗。
A window having such sashes; a casement window.Wp
暗炮台。
A casemate. Some writers and readers consider casement a catachresis when used in this sense.
She opened the casement to let in the cool morning breeze.
她打开平开窗，让凉爽的晨风吹进来。
The bedroom has two casements that open outward.
卧室有两扇向外开的平开窗。
He stood by the casement and watched the rain.
他站在平开窗旁，看着下雨。
casement 常作定语修饰 window，表示平开窗。
The bedroom has a casement window that opens outward.
这间卧室有一扇向外打开的平开窗。
casement 可单独指铰链连接的窗扇或整扇平开窗。
She opened the casement to let in the morning air.
她打开平开窗让早晨的空气进来。
Not this
There is a casement on the wall.
Use this
There is a casement in the wall.
窗户或窗扇位于墙洞中，介词应用 in，不用 on。汉语“在墙上”既可指挂在表面，也可指嵌在墙里，直译成 on 是中式英语，应改用 in。
Not this
The old house has two casement.
Use this
The old house has two casements.
casement 是可数名词，表示“两扇窗扇”时要在词尾加 -s，写成 casements。汉语名词没有复数变化，学习者容易漏掉 -s。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
平开窗
He replaced the old casement window with a modern double-glazed one.
他用现代的双层玻璃平开窗换掉了旧平开窗。
平开窗锁
Make sure to fasten the casement lock before you leave.
离开前务必锁好平开窗锁。
平开窗铰链
The casement hinge was rusted and needed oiling.
平开窗铰链生锈了，需要上油。
平开窗撑杆
Use the casement stay to hold the window open at an angle.
用平开窗撑杆把窗户斜着撑开。
被魔咒的窗扉，朝向危险之海的浪花敞开，在那荒凉的仙乡。
From John Keats's poem 'Ode to a Nightingale' (1819). The phrase 'magic casements' evokes the power of imagination to create enchanting, otherworldly visions.
出自约翰·济慈的诗歌《夜莺颂》（1819年）。“magic casements”这一短语唤起想象力创造迷人、超脱尘世景象的力量。
Use casement naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
casement 像 case(盒子)+ment：一扇像盒子盖一样从一侧翻开的小窗，记住平开窗扇。
语域：mixed 常见场景：建筑说明、房屋描述 casement 单独使用时常见于建筑、产品说明或维修类文字，多偏书面；日常交谈中更常搭配 window 说成 casement window。正式程度会随语境变化，通常可视为中性偏正式。
指一侧铰接的窗扇（通常单侧开合），并非整扇窗户。
Dictionary facts from ECDICT, WIKTIONARY.