Siad or SIAD may refer to: Siad (name) Șiad, a village in Craiva, Romania Self-injury Awareness Day, a grassroots annual global awareness event on March 1 Sierra Army Depot, California, United States Syndrome of inappropriate antidiuresis, a syndrome characterized by excessive unsuppressible release of antidiuretic hormone Surrey Institute of Art & Design, University College in the United Kingdom Supersonic Inflatable Aerodynamic Decelerator (SIAD), the main part of Low-Density Supersonic Decelerator