How Large is a Large Matrix ?

I was looking through the LAPACK documentation and came across various instances where there are different routines recommended for large and small matrices. For eg., SYEVD vs SYEVR ( https://software.intel.com/en-us/node/469180 ) - { last paragraph of the description section } .

But nowhere that I could find, is there any mention of how large, large exactly is. Does someone here know?

Thanks!