苦く土どくどMeanings1nounmagnesia; magnesium oxideTechnical term for magnesium oxide, used in chemistry, agriculture, and industry. Often seen in compound words like 苦土石灰 (magnesium lime).See also: 酸化マグネシウム苦く土どは肥ひ料りょうの成せい分ぶんとして使つかわれる。Magnesia is used as a component of fertilizer.苦く土ど石