A reversible reaction is a reaction that can proceed appreciably in both the forward and the reverse direction, and is represented by a double arrow (⇌). Such a reaction can reach a state of dynamic equilibrium, in which the forward and reverse rates are equal. It contrasts with an irreversible reaction, which goes essentially to completion in one direction.

可逆反应是能在正、逆两个方向上都明显进行的反应,用双箭头(⇌)表示。这类反应可达到动态平衡状态,此时正、逆反应速率相等。它与不可逆反应相对,后者基本朝一个方向进行到底。