3 times Excellent/Ideal in Cut & Polish & Symmetry = "Triple Ex".
Especially for round diamonds, the expression "3 times Excellent = Triple Ex" is a technical term for absolute top class → three times the very best category (Ideal or Excellent) for cut, polish, symmetry.
"Triple Ex" are diamonds that are classified in both Cut, Polish and Symmetry with an excellent in the diamond certificate -> 3 times excellent.
Since IGI "ideal" cut grade is even slightly better than excellent, "Triple Ex" of course also applies when a diamond has an ideal cut (although the wording is not 3x excellent).
IMPORTANT: IGI's "Ideal" = better than GIA Excellent! (though both cuts are excellent). IGI has an additional level for Best-of-Best of Excellent = ideal. This sometimes causes confusion as people think it has to be 3x Ex but ideal is even better.
Triple Ex stones are classified as follows:
ideal (better) or excellent cut excellent polish excellent symmetry