Definitions:

1. In astronomy context, refers to changes in solar radiation or geomagnetic activity due to the Earth's rotation. NOUN
   • Daily variation in solar radiation influences Earth's weather patterns and climate.
2. In environmental science context, involves changes in pollution levels, tidal movements, or wildlife activity that fluctuate over a 24-hour period. NOUN
   • Daily variation in air quality can be influenced by traffic patterns and industrial activity.
3. In finance and economics, refers to the changes in stock prices, currency values, or market indices that occur within a single trading day. NOUN
   • Investors monitor the daily variation of the stock market to make informed trading decisions.
4. In health and physiology context, describes fluctuations in biological functions such as hormone levels, blood pressure, or sleep patterns that follow a daily cycle. NOUN
   • There is a daily variation in cortisol levels, which typically peak in the early morning and decline throughout the day.
5. In meteorology contexts, refers to the changes in temperature, humidity, wind patterns, or atmospheric pressure that occur over a single day. NOUN
   • The daily variation in temperature can be extreme in desert regions, with hot days and cool nights.
6. Refers to the regular and often measurable changes or fluctuations that occur within a 24-hour period. NOUN
   • Wildlife populations experience daily variations in activity levels, depending on factors like prey availability, and predator presence.

Synonyms:

• 24-hour cycle
• daily fluctuation
• diurnal variation