noun
door frame; window frame; structural frame sections
Refers to the frame sections of a door or window that provide most of its structural integrity. A technical carpentry term.
このドアのかまちが歪んでいるので、閉まりにくい。
The door frame is warped, so it's hard to close.
窓のかまちを新しいものに交換した。
I replaced the window frame with a new one.
枠 is a general term for frame, border, or enclosure, while かまち specifically refers to the structural frame sections of doors and windows.
The origin is uncertain. The kanji 框 is used for its meaning 'frame' or 'enclosure', but the word itself is likely a native Japanese term.