casement

/K EY1 S M AH0 N T/
noun
  1. 1

    A window sash that is hinged on the side.

  2. 2

    A window having such sashes; a casement window.Wp

  3. 3

    Occasionally seen as a usage error due to the similarity of the words: A casemate.

Source: https://en.wiktionary.org/wiki/casement