TokenWords is an option for Read and related functions which gives a list of token words to be used to delimit words.
Top
(Built-in Mathematica Symbol) Top is a symbol that represents the top for purposes of alignment and positioning.
ToRules
(Built-in Mathematica Symbol) ToRules[eqns] takes logical combinations of equations, in the form generated by Roots and Reduce, and converts them to lists of rules, of the form produced by Solve.
TraditionalFunctionNotation is an option for selections that specifies whether input of the form f(x) is interpreted by the kernel as a function or as a product.
TrigFactorList[expr] factors trigonometric functions in expr, yielding a list of lists containing trigonometric monomials and exponents.
TrueQ
(Built-in Mathematica Symbol) TrueQ[expr] yields True if expr is True, and yields False otherwise.
UnderBar[expr] displays with a bar under expr.
Underflow[] represents a number too small to represent explicitly on your computer system.
Underlined represents an underlined font.
UnderoverscriptBoxOptions -> {opt_1 -> val_1, opt_2 -> val_2, ...} is an option for selections that specifies settings for UnderoverscriptBox objects.