What Is Dew?

The noun 'dew' means the small drops of water (dewdrops) which can be found on cool surfaces, such as grass, in the early morning. This is the result of atmospheric vapour condensing (reducing to liquid) on these surfaces in the colder night air. The temperature at which this condensation starts to take place is called dew point.
The word 'dew' is often used poetically to suggest freshness, moisture or even innocence in phrases such as 'dewy-eyed.' Occasionally the verb form 'to bedew' is used ('her pillow was bedewed with tears') but this is old-fashioned and very rare.

Dew is moisture witch develops over night.