There are 52 full weeks in a year of 12 months (ISO 8601 defines a year as containing 52 or 53 weeks), making for a possible 26 or 104 biweekly events in a year. This is a greater number than if such events were held twice a month, because most months have more than four weeks (28 days).
In the United Kingdom, Ireland, Australia and New Zealand, the term fortnightly is more commonly used for an event that occurs every two weeks. In the US, a biweekly publication is issued every two weeks and a bimonthly publication is issued every two months.
The term bifortnightly is rarely used as it, too, is ambiguous in meaning (either every four weeks or four times weekly).
References and Notes
|Look up biweekly in Wiktionary, the free dictionary.|