Occurring twice per month. For example, if salaried personnel are paid on the 15th and the last day of the month, we would say they are paid semimonthly. People paid semimonthly will receive 24 paychecks during a year. (People paid every two weeks - such as every other Thursday - are said to be paid biweekly and will receive 26 paychecks during the year). Also see mixed costs.