rs

RS is a two-letter designation that appears in several unrelated fields and contexts. Its meaning depends on the domain, and it is used as a code, a file extension, and as part of historical standard names in engineering.

In geography and information technology, RS most commonly refers to Serbia. It is the ISO 3166-1 alpha-2 country code for Serbia, and the country’s internet top-level domain is .rs. The RS designation appears in international data standards, shipping identifiers, and web addresses associated with Serbian entities.

In computing, rs is the standard file extension for Rust source code. The Rust programming language uses files with the .rs extension, and development tools, documentation, and code repositories recognize this extension as indicating Rust source files.

RS also appears in engineering and telecommunications as an abbreviation for “Recommended Standard.” This usage is found in historical serial-communication standards, such as RS-232 and RS-485, which specify electrical characteristics and signaling conventions for data transmission.

See also: country codes, programming languages, and historical standards.