semi-monthly

adjective

1. made, occurring, done, or published twice a month.

noun, plural sem·i·month·lies.

2. something occurring every half month or twice a month.
3. a semimonthly publication.

adverb

4. twice a month: We went semimonthly to see her.

adj.also semimonthly, 1809, from semi- + monthly.