Standards terminologies emerged as an attempt to reduce the diversity terminology in scientific languages, facilitating good communication, which is the basis of all scientific research. This review explains principles and applications associated with terminologies and classification systems focusing mainly on the field of biomedical sciences. The research was conducted on scientific databases, books and network using the keywords: Terminologies, Classification systems, Medical Informatics, Electronic Health Records systems, Interoperability, Ontologies and Bio-ontologies. This review is intended to explain that terminologies facilitate good communication, reducing terminology diversity and they are not static systems. They can evolve to more complex structures like biomedical ontologies, with the aim of being used with multiple purposes beginning with the efficient transfer of information, to the processing of information as a result of biological research for its understanding.