A group of organisms sharing similar characteristics is called a species.

However, there are other levels of classification that also group organisms based on shared traits:

* Genus: A group of closely related species.

* Family: A group of related genera.

* Order: A group of related families.

* Class: A group of related orders.

* Phylum: A group of related classes.

* Kingdom: A group of related phyla.

* Domain: The highest level of classification, grouping organisms based on fundamental cellular characteristics.

So, while "species" is the most specific answer to your question, there are many other levels of grouping organisms based on shared characteristics.