It means the same thing in MATLAB and numpy:

   Z = np.array([[1,2,3]])
   W = Z + Z.T
   print(W)

   [[2 3 4]
    [3 4 5]
    [4 5 6]]

[1] https://numpy.org/devdocs/user/basics.broadcasting.html#gene...

One of the really nice things Julia does is make broadcasting explicit. The way you would write this in Julia is

    Z = [1,2,3]

    W = Z .+ Z' # note the . before the + that makes this a broadcasted