Thin
(Built-in Mathematica Symbol) Thin is a graphics directive that specifies that lines which follow should be drawn thin.
ToUpperCase[string] yields a string in which all letters have been converted to uppercase.
TraceOff is an option for Trace and related functions which specifies forms inside which tracing should be switched off.
TransformationMatrix[tfun] gives the homogeneous matrix associated with a TransformationFunction object.
UnderoverscriptBox[x, y, z] is the low-level box representation for x_y^z in notebook expressions.
WeierstrassInvariants[{\[Omega], \[Omega]^\[Prime]}] gives the invariants {g_2, g_3} for Weierstrass elliptic functions corresponding to the half-periods {\[Omega], ...
$ContextPath is a global variable that gives a list of contexts, after $Context, to search in trying to find a symbol that has been entered.
$CurrentLink is the LinkObject representing the MathLink connection for an external program currently being installed or being called.
$KernelID is a unique ID number assigned to each running parallel kernel.
$MaxNumber gives the maximum arbitrary-precision number that can be represented on a particular computer system.