Definition of "SO"

Initialism of significant other.  examples

(sports) Initialism of shut out.  examples

(sports) Initialism of shootout.  examples

(baseball) Initialism of strike out.  examples

(logic, computer science) Initialism of second-order logic.  examples

(music) Initialism of symphony orchestra.  examples

(chemistry) Abbreviation of singlet oxygen.  examples

Initialism of someone.  examples