This work presents another concept of observability in nonlinear systems, when the states of these types of models are described using a representation by interval numbers. This approach is an extension of classical concepts of nonlinear observability, called ε-observability and is based on a notion of the neighborhood of a state with a given precision of epsilon. Our proposal includes the notion of an indistinguishable trajectory by intervals applied to the IMHSE method, which is the basic concept used to construct the notions of observability that will be presented.