RA may refer to:

• Right ascension, an astronomical term
• Relation algebra, a type of mathematical structure

Ra (; , ) or Re (; , Re) is the ancient Egyptian sun god. By the Fifth Dynasty in the 25th and 24th centuries , he had become a major god in ancient Egyptian religion, identified primarily with the noon sun.

In Scandinavian folklore, a rå , is a keeper or warden of a particular location or landform. The different species of rå are sometimes distinguished according to the different spheres of nature with which they were connected, such as skogsrå or huldra (forest), sjörå (freshwater) or havsrå (saltwater), and bergsrå (mountains).

Ra is the Sun-god of Ancient Egypt.

RealAudio is a proprietary audio format developed by RealNetworks and first released in April 1995. It uses a variety of audio codecs, ranging from low-bitrate formats that can be used over dialup modems, to high-fidelity formats for music. It can also be used as a streaming audio format, that is played at the same time as it is downloaded. In the past, many internet radio stations used RealAudio to stream their programming over the internet in real time. In recent years, however, the format has become less common and has given way to more popular audio formats. RealAudio was heavily used by the BBC websites until 2009, though it was discontinued due to its declining use. BBC World Service, the last of the BBC websites to use RealAudio, discontinued its usage in March 2011.

In Maori mythology, Tama-nui-te-ra (Tamanuitera) is the personification of the Sun.