noun Chemistry, Physics.
- a superheavy, synthetic, radioactive element with a very short half-life. Symbol: Sg; atomic number: 106.
- a synthetic transuranic element, synthesized and identified in 1974. Symbol: Sg; atomic no: 106
- A synthetic, radioactive element that is produced by bombarding californium with oxygen ions or bombarding lead with chromium ions. Its most long-lived isotopes have mass numbers 259, 261, 263, 265, and 266 with half-lives of 0.9, 0.23, 0.8, 16, and 20 seconds, respectively. Atomic number 106. See Periodic Table.