"Half-hour" is a commonly used term to refer to 30 minutes of time. However, there are several synonyms that can be used interchangeably with the term "half-hour". Some of the most common synonyms for "half-hour" include "thirty minutes", "30 minutes", "a half of an hour", "one-half of an hour" and "a half-hour interval". In addition, there are also some regional variations in terms of synonyms, such as "a half-six" in Ireland, which means half-past six (or 6:30 PM). Regardless of the specific wording, these synonyms all refer to the same period of time and can be used in the same context.