Two million people gathered in the streets of Rome ... celebrating the Italian capital's second annual all-night cultural extravaganza.
When we describe events that take place regularly, we can use a phrase that describes exactly how frequently they take place.
Examples: The school organises a picnic once a year.
The English Club holds a meeting once a week.
However, sometimes we need an adjective, instead of a phrase, to describe the event.
Examples: I was sick yesterday, so I couldn't go to the school's annual picnic.
If you wish to join the English Club, simply go to their weekly meeting and speak to them.
Below are some common frequency adjectives:
biannual: twice a year
biennial: once every two years
fortnightly: once every two weeks ('biweekly' in American English)
Be careful with bimonthly, as it can mean 'every two months' or 'twice a month'.