Is there a word in English language that means "every eight weeks"? [duplicate]

Solution 1:

You can make a compound out of a number and period suffixed '-ly'. Four-hourly, two-weekly, six-monthly, five-yearly.

Eight-weekly intravenous antibiotics is beneficial in severe bronchiectasis

National Library of Medicine

The time commitment for all of these positions will involve six-weekly meetings of both the Labour Group Executive and the main Labour Group Councillors

to organise the logistics of their six-weekly meetings, ensuring that everyone gets to everywhere they need to go across their visits

Solution 2:

bimonthly, though it can be confusing:

Bimonthly is one of a group of confusing words (including biweekly and biannually) that have two meanings. You can use bimonthly to mean both "twice a month" and "every two months." The roots of the word are the Latin bi-, "twice" or "double," and monthly. (Vocabulary.com)

You might need to clarify the meaning in your context. Consider this example given by Cambridge:

The magazine is published bimonthly, with six issues a year.

As alternatives, WordHippo gives every other month or every two months. Every 8 weeks looks over explicit.

Gngram seems to give preference to bimonthly.