This acronym stands for:

  • S&I
  • Science & Industry (gaming, Half_Life mod) (S&I)
  • Security and Intelligence (various organizations) (S&I)
  • Savings and Investment (S&I)
  • Systems and Information (S&I)
  • Supply and Installation (S&I)
  • Supervision and Inspection (USACE) (S&I)
  • Salt and Ice (S&I)
  • Supervision and Interpretation (medical) (S&I)
  • Survey & Investigation (S&I)
  • Science and Innovation Network (British Foreign and Commonwealth Office; UK) (S&I)
  • Suction and Irrigation (surgery) (S&I)
  • Standardization & Interoperability (S&I)
  • Seminaries and Institutes of Religion (S&I)
  • Switchgear and Instrumentation Limited (electrical control) (S&I)
  • Sensing and Imaging (terahertz science) (S&I)