The first time I ever heard the word "fortnight" was when somebody told me that one furlong per fortnight is almost exactly 1 cm per minute.
That was also the first time I was exposed to the word "furlong". You can imagine my confusion.
@j_bertolotti North American English speakers need to get on board with fortnight, because otherwise you’re stuck with the whole bi-monthly mess.

@john @j_bertolotti Problem 1: It's unclear whether "biweekly" means "twice a week" or "once in two weeks".
Problem 2: It's unclear whether "bimonthly" means "twice a month" or "once in two months".

"Fortnight" swoops in to save the day! Once in two weeks = twice a month = "fortnightly". Now "biweekly" and "bimonthly" need to only mean one thing!

Problem 3: Now "bi-" means completely opposite things in "biweekly" and "bimonthly".

@narain @j_bertolotti I propose not holding things twice a week, it’s too often.