R50

R50 is a designation used in several unrelated fields to label different products, codes, and safety terms. It does not have a single, universal meaning.

In transportation and machinery, R50 appears in the BMW R50/2, a classic motorcycle produced from 1955 to 1969. The R50/2 was part of BMW's R50 line and used a 500cc air-cooled flat-twin engine, characteristic of the company's early Box­er motorcycles.

In medicine, R50 is used in the ICD-10-CM coding system as the prefix for fever-related diagnoses. The code R50.9 corresponds to fever, unspecified.

In chemical safety labeling, R50 is a risk phrase meaning "Very toxic to aquatic life." It was part of the older R-phrase system used in the European Union; many labels have since transitioned to GHS hazard statements, but R50 remains encountered in historical or legacy documents.