Small interfering RNA (siRNA) is a term commonly used in molecular biology research to refer to a type of RNA molecule that plays an important role in gene regulation. Other synonyms for siRNA include short interfering RNA, short RNA duplexes, and silencing RNA. Each of these terms describes a similar type of molecule, with a length of around 21-25 nucleotides, and the ability to interact with messenger RNA (mRNA) to degrade or block its translation into protein. siRNA molecules are being studied for their potential therapeutic applications in treating diseases such as cancer, viral infections, and genetic disorders.