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. 2019
Examples from the Web for semidiurnal
Historical Examples of 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
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012