What is an array of arrays called when all arrays have the same size? If I have an array a of arrays, in many languages they may have different size. Is there a word for an array of arrays where all the arrays have the same length?

Edit:
An array of arrays may have the following form:


[ 
  [ 1, 2, 3 ]
  [ 1, 2, 3, 4 ]
  [ 1, 2 ]
]


But in order to convert this to a matrix you would have to assume some default value or trim the arrays. The following array of arrays is possible to convert into a matrix without any asumptions or trimming as all arrays have same length.


[ 
  [ 1, 2, 3, 4 ]
  [ 1, 2, 3, 4 ]
  [ 1, 2, 3, 4 ]
]


Is there some name or classifier for a matrix of this kind?
In C# world there are 2 kinds of array declarations, and 2 names for it:


Jagged:



[ 
  [ 1, 2, 3 ]
  [ 1, 2, 3, 4 ]
  [ 1, 2 ]
]



Rectangular:



[ 
  [ 1, 2, 3, 4 ]
  [ 1, 2, 3, 4 ]
  [ 1, 2, 4, 4 ]
]