1. Occurring twice per week (this is true no matter what Dan or his English professor mom says. My mom was a book editor and she looked it up in the dictionary. I don't care that she originally thought it was definition #2. She found it in Merriam Webster, the dictionary Dan recommended).
2. (Occ.) Every two weeks.
The College of William and Mary's Flat Hat newspaper is published biweekly, allowing me to read it twice every week.
Because biweekly first and foremost means twice per week, I do not owe Dan any money.