Eugène Ionesco belongs to a group of dramatists known as the Theater of the Absurd, a concept coined by Martin Esslin. I argue that this concept of the absurd is inconsistent since the definition is linked to the opinions and conventions of each era. Therefore, the term absurd is imprecise when applied to theater, an art form that is directly linked to the period in which it is written and in which it is performed. I propose the idea of anti-theater, a concept mentioned by Ionesco within his work, to better define Ionesco's plays.