According to Etymonline, biweekly(twice a week) is older, but the word itself is linguistically ambivalent and nowadays more commonly used to refer to once every two weeks.
Semiweekly can be used for 'twice a week', and predates the usage of biweekly by nearly 70 years.
And fortnight (and presumably fortnightly) goes back way further and originated as a compound of 'fourteen nights'.
...Looking that up was actually far more interesting than I expected.
Semiweekly can be used for 'twice a week', and predates the usage of biweekly by nearly 70 years.
And fortnight (and presumably fortnightly) goes back way further and originated as a compound of 'fourteen nights'.
...Looking that up was actually far more interesting than I expected.