Ondol definitions

Ondol

1) Korean architecture 2) Korean invention
Found on https://www.crosswordclues.com/clue/ondol

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ondol

(from the article `Korea, history of`) ...). About this time ironware came to be used. Iron plows and sickles indicate the use of animals in farming and more efficient harvesting methods. ...
Found on http://www.britannica.com/eb/a-z/o/20

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