How exactly were Pyrrhus's victories "pyyrhic victories"?

Because, by definition, any victory one by Pyrrhus would be Pyrric, given that those victories were made in a manner owing to him.

>>3358464
Because he took losses he couldn't replace, and while he put the hurt on the Romans, he came no closer to actually forcing them to surrender after battles like Heraclia and Asculum. He won the field, but fell further behind when it came to the actual winning of the war.

Also, I would point out that in classical battle, losing around 10% of your forces when you win was pretty rare and makes it a messy win. Go look up land battles, especially among the Hellenics, and you see that the losing side didn't always lose that many men, and the winning side, almost never. Those kinds of losses were damn heavy for "victory".