RadicalBox[x, n] is a low-level box construct that represents the displayed object Power[x, (n)^-1] in notebook expressions.
RowBox
(Built-in Mathematica Symbol) RowBox[{box_1, box_2, ...}] is a low-level box construct that represents a row of boxes or strings in a notebook expression.
Subscript[x, y] is an object that formats as x_y. Subscript[x, y_1, y_2, ...] formats as x Subscript[y, 1], Subscript[y, 2], ....
Thinning[image] finds the skeletons of foreground regions in image by applying morphological thinning until convergence.Thinning[image, n] performs n iterations of ...
TimeUsed[] gives the total number of seconds of CPU time used so far in the current Mathematica session.
WindowTitle is an option that specifies the title to give for a window.
$PreRead is a global variable whose value, if set, is applied to the text or box form of every input expression before it is fed to Mathematica.
NotebookConvertSettings -> {opt_1 -> val_1, opt_2 -> val_2, ...} is a global option that specifies settings for converting imported legacy notebooks.
Binary
(Mathematica Import/Export Format) Sequence of binary data objects. Binary format. Stores a uniform sequence of simple or compound data types.
DeBruijnSequence[a, n] returns a De Bruijn sequence on the alphabet a, a shortest sequence in which every string of length n on alphabet a occurs as a contiguous subsequence.