semihourly

/S EH1 M AH0 HH AW0 R L IY0/
adjective
  1. 1

    (properly) Half-hourly: occurring every thirty minutes.

  2. 2

    (inexact) Roughly (but not exactly) hourly: occurring around every sixty minutes.

adverb
  1. 1

    (properly) Half-hourly: at intervals of 30 minutes.

  2. 2

    (inexact) Roughly (but not exactly) hourly: at intervals of around 60 minutes.