Rectangular array that's identical when its rows and columns are transposed, as this puzzle's grid

Question:

Answer:

SYMMETRICMATRIX

Length:

Similar Crossword Questions:

Web concerns ... and based on six familiar names hidden in rows 1, 4, 12 and 15 of this puzzle grid, what the black squares in those rows symbolize
Array in mathematics with the same number of rows and columns
On hold ... or what the seven rows of black squares in this puzzle's grid spell in Morse code
Where to look for hidden words in this puzzle's fifth and eleventh columns?
First word across in the first-ever crossword (1913) and the first of a dozen appearances of the word in this puzzle's grid, written word search-style (left, right, down, and diagonally) ... Can you f
Set of which all seven elements are fittingly hidden in the solved puzzle grid
Last letter in most plurals (but not in this puzzle's six longest answers, which are the only plurals in this grid)
What you can find in the grid after completing this puzzle, looking up, down, left, right and diagonally, word search-style
Pleased look (as depicted by this puzzle's grid)
Theme of this puzzle, whose members are hidden throughout the grid
What this puzzle's three identical clues can represent
Setup of rows and columns
Paper puzzle usually involving a 9x9 grid (2004)
Classic Belushi comedy, or an apt description of this puzzle's grid?
The 2x2 black square near the middle of this puzzle's grid, e.g., which is part of eight answers
God with a weekday named after him who can be found in this puzzle's three grid-spanning entries
Descriptive of this puzzle's grid
Unlike this puzzle's grid
Award won by lead actors in this puzzle's starred films: the winners' names are hidden "word search"-style in the grid (across, down or diagonally, and forward or backward)
Image this puzzle grid is supposed to suggest
Result of not following through (of which there are four examples in this puzzle's grid)
Its rows, columns and diagonals all add up to the same number
Like this puzzle's grid
Like aleph in the central black squares of this puzzle's grid
Legend born 4/24/1942 whose name's 9 letters are the only ones in this puzzle grid