[keys-muh nt]


a window sash opening on hinges that are generally attached to the upright side of its frame.
Also called casement window. a window with such a sash or sashes.
a casing or covering.

Origin of casement

1375–1425; late Middle English. See case2, -ment
Related formscase·ment·ed, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for casement-window



a window frame that is hinged on one side
a window containing frames hinged at the side or at the top or bottom
a poetic word for window

Word Origin for casement

C15: probably from Old Northern French encassement frame, from encasser to frame, encase, from casse framework, crate, case ²



Sir Roger (David). 1864–1916, British diplomat and Irish nationalist: hanged by the British for treason in attempting to gain German support for Irish independence
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for casement-window



type of hinged sash-window that swings open like doors, early 15c., "hollow molding," probably a shortening of Old French dialectal enchassement "window frame" (Modern French enchâssement), from en- "in," prefix forming verbs, + casse "case, frame" (see case (n.2)) + -ment. Or possibly from Anglo-Latin cassementum, from casse. The "window" sense is from 1550s in English. Old folk etymology tended to make it gazement.

The Irish surname is originally Mc Casmonde (attested from 1429), from Mac Asmundr, from Irish mac "son of" + Old Norse Asmundr "god protector."

Online Etymology Dictionary, © 2010 Douglas Harper