thilln. 轅、車把學術名詞煤層底板:礦物學、海洋地質學底黏土:礦物學、海洋地質學底磐泥:礦冶工程薄層耐火黏土:礦物學英文釋義one of two shafts extending from the body of a cart or carriage on either side of the animal that pulls it