Somalia, previously known as the Somali Democratic Republic

Software-Defined Radio, radio communication system which uses software for the modulation and demodulation of radio signals

Strategic Defence Review, a United Kingdom Ministry of Defence defence review

Special Drawing Rights, in the International Monetary Fund

System of distinct representatives, in mathematics

ETSI Satellite Digital Radio (SDR)

Santander Airport, IATA airport code

Sudden Death Records

Süddeutscher Rundfunk, a former German radio station

System Design Review, a scheduled review which ensures continuous involvement throughout a program

Snailbeach District Railways, a mine railway running from Snailbeach to Pontesbury