Section: Array Generation and Manipulations
iscellstr is
x = iscellstr(y)
and it returns a logical 1 if the argument is a cell array in which every cell is a character array (or is empty), and a logical 0 otherwise.
--> A = {'Hello','Yellow';'Mellow','Othello'}
A =
<cell array> - size: [2 2]
Columns 1 to 2
Hello Yellow
Mellow Othello
--> iscellstr(A)
ans =
<logical> - size: [1 1]
1