The word "bimonthly", like its cousins "biweekly" and "biyearly", has two similar but different meanings. Its original meaning was "once every two months," but over time it has also evolved the meaning "twice in one month." This makes for confusion, and puts "bimonthly" in a unique category of words with dual or unexpected meanings, like cleave and inflammable.
Bi*month"ly (?), a. [Pref. bi- + monthly.]
Occurring, done, or coming, once in two months; as, bimonthly visits; bimonthly publications.
n.
A bimonthly publication.
© Webster 1913.
Bi*month"ly, adv.
Once in two months.
Log in or register to write something here or to contact authors.