on the half hour

on the half hour

1. Happening hourly, but at 30 minutes past each hour; ie, 08:30, 09:30 etc.

   Trains leave here for New York every hour on the half hour.

2. Happening on the hour and at 30 minutes after the hour.
   • 2011, Studs Terkel, "The Good War": An Oral History of World War II‎:

     In one corner is an old grandfather's clock; the chimes are on the half-hour.

   • 2010, Stephanie Cowell, Claude & Camille‎, page 248:

     He bought and framed Japanese prints, and she chose a bronze mantelpiece clock with a silver bell that struck on the half hour.

3. (soccer) At thirty minutes into a half.

• on the hour
• top of the hour