The inequality in educational resources between urban and rural areas is a serious social issue.

inequality 是由前缀 in-（表示"否定"）和 equality（"平等"）组成的复合名词。equality 来自形容词 equal（"平等的"）加上名词后缀 -ity。整个词的字面意思是"不平等"，指资源、机会等方面的差异或不公平现象。