TableForm[list] prints with the elements of list arranged in an array of rectangular cells.
The height of each row and the width of each column are determined by the maximum size of an element in the row or column.
TableForm prints a single-level list in a column. It prints a two-level list as a two-dimensional table. More deeply nested lists are by default printed with successive dimensions alternating between rows and columns.
Arrays in which all sublists at a particular level are not of the same length display as ragged tables.
The following options can be given:
TableForm acts as a "wrapper", which affects printing, but not evaluation.
See The Mathematica Book: Section 1.8.2 and Section 2.8.8.
See also: ColumnForm, MatrixForm, GridBox, GraphicsArray.