Nouns

(n)bimonthlya periodical that is published twice a month or every two months (either 24 or 6 issues per year)

Adjectives

(s)semimonthly, bimonthlyoccurring twice a month“a semimonthly publication”
(s)bimonthly, bimestrialoccurring every two months“bimonthly visits”

Adverbs

(r)semimonthly, bimonthlytwice a month“salaries are paid semimonthly”
(r)bimonthlyevery two months“the bill was payable bimonthly”