SquareWave[x] gives a square wave that alternates between +1 and -1 with unit period.SquareWave[{y_1, y_2}, x] gives a square wave that alternates between y_1 and y_2 with ...
StringTake["string", n] gives a string containing the first n characters in " string". StringTake["string", -n] gives the last n characters in " string". StringTake["string", ...
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.
StyleBox[boxes, options] is a low-level representation of boxes to be shown with the specified option settings. StyleBox[boxes, " style"] uses the option setting for the ...
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.
TakeWhile[list, crit] gives elements e_i from the beginning of list, continuing so long as crit[e_i] is True.
TextCell["string"] gives a text cell that can appear in a Mathematica notebook.TextCell["string", " style"] gives a text cell with the specified style.
TextPacket[string] is a MathLink packet containing string, the text output from Mathematica as produced by functions such as Print.
Tiny
(Built-in Mathematica Symbol) Tiny is a style or option setting that specifies that objects should be tiny.