Semi-weekly refers to something that occurs twice a week. Some synonyms for this word include "biweekly," "fortnightly," and "every other week." Bi-weekly also means something occurring twice a week, but it can also mean something that happens every two weeks, which can cause confusion. Fortnightly is used mainly in British English and means something that occurs every two weeks. Every other week means that something occurs alternately every two weeks. While these words have slightly different meanings, they can be used interchangeably with semi-weekly in most cases. Whatever synonym you choose to use, it is important to ensure that the intended meaning is clear to your audience.