semihourly adjective 2adverb 2 adjective2 •Half-hourly: occurring every thirty minutes.The warship rang its semihourly bell, announcing it was now half past 10 o'clock. •Roughly (but not exactly) hourly: occurring around every sixty minutes. adverb2 •Half-hourly: at intervals of 30 minutes.Samples were collected semihourly (on the hour and half hour) throughout the study. •Roughly (but not exactly) hourly: at intervals of around 60 minutes.
