1) Mobile genetic element 
SaPIs (Staphylococcus aureus or superantigen pathogenicity islands) are a family of mobile genetic elements resident in the genome of some strains of Staphylococcus aureus. Much like bacteriophages, SaPIs can be transferred to uninfected cells and integrate into the host chromosome. Unlike the bacterial viruses, however, integrated SaPIs are mobil...
Service Access Point Identifier - a service layer address in OSI.
Speech Application Program Interface [Microsoft]
semi-armour-piercing incendiary