Stack
(Built-in Mathematica Symbol) Stack[] shows the current evaluation stack, giving a list of the tags associated with evaluations that are currently being done. Stack[pattern] gives a list of expressions ...
StringReverse["string"] reverses the order of the characters in " string".
TableHeadings is an option for TableForm and MatrixForm which gives the labels to be printed for entries in each dimension of a table or matrix.
TextJustification is an option for Cell and Inset which specifies how much lines of text can be stretched in order to make them be the same length.
Thick
(Built-in Mathematica Symbol) Thick is a graphics directive that specifies that lines which follow should be drawn thick.
Thin
(Built-in Mathematica Symbol) Thin is a graphics directive that specifies that lines which follow should be drawn thin.
TimeUsed[] gives the total number of seconds of CPU time used so far in the current Mathematica session.
ToCharacterCode["string"] gives a list of the integer codes corresponding to the characters in a string. ToCharacterCode["string", " encoding"] gives integer codes according ...
ToUpperCase[string] yields a string in which all letters have been converted to uppercase.
TraceDialog[expr] initiates a dialog for every expression used in the evaluation of expr. TraceDialog[expr, form] initiates a dialog only for expressions which match form. ...