1. A pirate who steals, pillages, and acts generally badass for the purpose of obtaining pie.
2. A pirate who IS a pie.
3. The ever rising costs of pie.
4. One (most often a pierate) who has eaten an entire pier, mistaking it for a pie.
5. A ratio, approximately 1.15, equal to that of pi and e.
No specific examples, though the more badass a person is, the more likely it is that they are, in fact, a pierate.
Examples of people badass enough to be pierates, though they aren't: Aron Ralston, John Hirsch, Sigurdur Petursson (may be a pierate, unconfirmed), Edward Teach, Grigori Rasputin