SAS
n. uncountablen. Stands for Special Air Service. It is the elite special forces unit of the British Army. It is famous for its secret missions and very difficult training.
n. Abbreviation for Special Air Service. A special forces unit of the British Army known for high-risk operations and counter-terrorism. When used in this sense, it is usually preceded by the definite article.
He served in the SAS for ten years.
The government deployed the SAS to handle the hostage situation at the embassy because of their specialized training.
Selection for the SAS is notoriously rigorous, with only a small percentage of candidates successfully completing the endurance phases in the Welsh mountains to earn their place in the regiment.
Usually functions as a collective noun or proper name; typically takes the definite article 'the'.