在英语中 人比人,物比物的定义是定义（用法）.

你是说比较级的用法吧.
1.主系表结构
A+be动词+ 形容词的比较级 + than + B(代词一般用宾格).A比B……
如：He is taller than me.他比我高.
2.主谓宾结构
A + 谓语动词 + 副词比较级 + than + B.
如：He runs faster than me.他比我跑的快.
3.同级比较
A + 谓语 + as + 形容词原形或副词原形 + as + B.
如：He is as tall as me.他和我一样高.
He runs as fast as me.他和我跑得一样快.