{"era":"current","word":"reservoir","meaning":"A large natural or artificial lake used as a source of water supply.","children":[{"era":"17th century","word":"réservoir","meaning":"a place for keeping things","children":[{"era":"13th century","word":"réserver","meaning":"to keep, to save","children":[{"era":"classical","word":"reservare","meaning":"to keep back, reserve","children":[],"language":"Latin"}],"language":"Old French"}],"language":"French"}],"language":"Modern English"}