SpellingCorrection is an option for StringMatchQ, Names, and related functions that specifies whether strings should be considered to match even when a small fraction of the ...
SphericalHankelH2[n, z] gives the spherical Hankel function of the second kind h_n^(2)(z).
SplineClosed is an option for B-spline functions and graphics primitives that specifies whether spline curves or surfaces should be closed.
StructuredSelection is an option for Cell that specifies whether to allow only complete subexpressions in the cell to be selected interactively using the front end.
SystemHelpPath is a global option that specifies which directories are searched for the help notebooks used within the help system.
TabSpacings is an option for character selections that specifies the number of spaces in ems that the cursor advances when the Tab key is pressed.
TaggingRules is an option for selections that specifies a list of strings to be associated with a selection.
ThompsonGroupTh[] represents the sporadic simple Thompson group Th.
UnderBar[expr] displays with a bar under expr.
Underlined represents an underlined font.