柯林斯詞典reactant /r???kt?nt/ 1. N a substance that participates in a chemical reaction, esp a substance that is present at the start of the reaction 反應(yīng)物→compare product 返回 reactant劍橋詞典a substance that is part of a chemical reaction （化學(xué)反應(yīng)中的）反應(yīng)躰，反應(yīng)物 返回 reactant