Nomenclature refers to either a list of names and/or terms, or to the system of principles,procedures and terms related to naming - which is the assigning of a word or phrase to a particular object or property.

 or simply you can say naming i.e. giving name to any compound through some conventions

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In this case, it refrers to the very structured system we have for naming organisms so that related organisms are grouped together.
The advantage is it allows for understanding just what an organism is based on the name, what order, what class, etc...

There are thousands of ant species but one of the carpenter ants is called Camponotus atriceps   !!!!!