R1

R1 is an alphanumeric designation used in multiple domains to identify the first item in a series, a first version or variant, or a standard reference. Its exact meaning depends on the context, but it generally signals primacy or a primary instance.

In electronics and circuit design, R1 often appears as a reference designator for a resistor in a schematic, typically appearing alongside other components such as R2, C1, and so on. In product branding, R1 is used in model names to indicate a first-generation or specific variant, as in sport or high-performance lines. A well-known example is the Yamaha YZF-R1, a sport motorcycle marketed as a premier, high-performance model.

In gaming hardware, R1 commonly denotes the right shoulder button on many controllers, including PlayStation controllers where the bumper is labeled L1/R1. In software development and documentation, r1 can mark revision 1 or release 1 of a document, firmware, or project version.

In mathematics and physics, r1 may be used as a variable or parameter, such as the first radius or distance in a defined system, often alongside related symbols like r2. Because r1 has diverse uses across fields, determining the precise meaning requires contextual information about the domain and the specific application.