Combine is a farm machine that cuts and threshes grain or other crops in one operation. The word combine stands for combined harvester-thresher. Some are large, self-powered machines. Others are smaller models pulled by tractors. Large combines cut paths wider than 20 feet (6 meters). Small ones cut paths about 6 feet (1.8 meters) wide. Those with special attachments can collect and shell corn, soybeans, and other crops.