We have two words for events occurring in periods of years – biannual meaning twice a year, and biennial meaning once every two years.
However, my colleagues talk about having meetings biweekly. This causes a lot of confusion, since it can mean either once every two weeks or twice a week.
We can use fortnightly to indicate once every two weeks and help disambiguate that way. Are there any other words we could use which could help, particularly words which mean "twice a week"? I'm looking particularly because some of my colleagues speak English only as a second language, and find fortnightly difficult to remember.