- pertaining to, consisting of, or accomplished in half a day.
- occurring every 12 hours or twice each day.
Origin of semidiurnal
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for semidiurnal
The semidiurnal tidal forces vanish at the Pole and are very small over the entire Arctic Ocean.The North Pole
Robert E. Peary
- of or continuing during half a day
- occurring every 12 hours