The word "seriscission" is not a commonly used term, but it refers to the act of cutting silk threads. The spelling of this word can be explained using IPA phonetic transcription as /sɛrɪˈsɪʃən/. The first syllable is pronounced with an "eh" sound, while the second syllable is pronounced with a short "i" sound. The "sc" in the third syllable is pronounced like "sh," giving way to a predominantly soft-sounding word. If you're discussing silk production, it's a term you may encounter!
Division of the pedicle of a tumor or other tissue by a silk ligature.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.