1. occurring twice a day
2. relating to or having a period of approximately half a day (about 12 hours)
Usage: technical

Examples

• The semidiurnal tides occur twice each day along most coastlines.
• Many medications require semidiurnal dosing for optimal effectiveness.
• The semidiurnal rhythm of certain hormones follows a 12-hour cycle.
• Semidiurnal temperature variations are most pronounced in desert regions.
• The patient was prescribed semidiurnal treatments to manage the condition.
• Ocean currents often display semidiurnal patterns of flow.