half-hour

noun

1. a period of 30 minutes.
2. the midpoint between the hours: The clock struck on the half-hour.

adjective

3. of, relating to, or consisting of a half-hour: half-hour programs.

noun

1. 1. a period of 30 minutes
   2. (as modifier)a half-hour stint on the treadmill
2. 1. the point of time 30 minutes after the beginning of an hour
   2. (as modifier)a half-hour chime

early 15c., from half + hour. Related: Half-hourly.