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

Question:

Answer:

SYMMETRICMATRIX

Length:

Similar Crossword Questions:

On hold ... or what the seven rows of black squares in this puzzle's grid spell in Morse code
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
It's entirely represented in this puzzle grid
Number of times this puzzle's theme word appears diagonally in the grid (to complete the puzzle, shade those words plus the Down answers that begin where they meet)
Theme of this puzzle, seen seven times in the grid
Number of F's in this puzzle's answer grid
New Year's tune transposed nine times in this puzzle
Arranged in rows and columns
Using both sides with equal frequency (like the letters in this puzzle's answer grid?)
Urban areas (as hinted at by the circled letters in this puzzle's grid)
Number of Qs in this puzzle's grid
Set up in rows and columns
Numerical puzzle with a 9x9 grid
Word appearing eight times in this puzzle grid
Edit rows and columns of data?
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
Last letter in most plurals (but not in this puzzle's six longest answers, which are the only plurals in this grid)
Set of which all seven elements are fittingly hidden in the solved puzzle grid
What you can find in the grid after completing this puzzle, looking up, down, left, right and diagonally, word search-style
Theme of this puzzle, whose members are hidden throughout the grid
What this puzzle's three identical clues can represent
Pleased look (as depicted by this puzzle's grid)
The 2x2 black square near the middle of this puzzle's grid, e.g., which is part of eight answers