There are some rune books that refer to the Dagaz rune as the rune of daybreak.  
I say, look at its shape.  Dagaz is a rune of wholeness.  It holds the energy of extremes.  It is daybreak and nightfall.  To name it daybreak is to speak of only half of it.  
It’s a balanced rune.  It’s even, and there’s a place in the middle, the still point, where the two extremes come together and at that point neither of them exists; they are both nothing.
Dagaz contains both sunrise and sunset, the power of night and day, dark and light as well as the point of intersection, the still point, the threshold, the liminal space.
It's interesting that in the English language the word day is used to include both day and night.  Have you ever thought about that?  We're all familiar with using the expression ‘an entire day’ to describe a 24-hour period.  Why don’t we say instead, ‘an entire night’?  Is it because we fear the dark?
If Dagaz holds both light and dark, we could easily call it the rune of nightfall and be just as correct as calling it the rune of daybreak, but such singular descriptions misrepresent the actual rune.  What if we refer to it instead as the rune of Equinox, a word that means equal night? 
I read an explanation once about the Dagaz rune where the person said, ‘darkness isn’t darkness.  It’s a quality of the light.’
I find that statement extremely strange.  And stranger still when attempting to apply it to the ancient wisdom of Dagaz.
Dark isn’t a quality of light any more than light is a quality of dark.  Darkness isn’t the absence of light any more than light is the absence of darkness. 
Many times when Dagaz appears in a reading it comes as an invitation to examine your relationship with and beliefs around darkness.
Dagaz will also show itself in times of transformation.  Often I use the example of the
metamorphosis of the caterpillar.  For a certain period of time, all the caterpillar does is eat.  Then at some moment it stops and begins to create from its own body a container that will enclose it and during the time of confinement it will go through a complete change in form.  The body of the caterpillar liquefies and when it reaches that place it's not unlike the single point of the Dagaz rune. It’s not one thing or the other.  It's nothing and it's no thing.  It’s the still point before the turning.
Everything that was needed to become something new was contained within the old and all that is needed to become again the old is contained within the new. 
Once transformed, the butterfly must emerge from the container and to do so requires struggle and persistence.  And once it emerges it must trust that its newly formed wings will allow it to fly.
Powerful, transformative things happen in the dark.  It takes stored energy to transform and it takes stored energy to emerge.  There are times during the transformation process that require silliness and waiting.  There are times during the process when it's necessary to wiggle and struggle to come forth.
Do you allow yourself to be still in order to transform?  Do you know how to effort in order to emerge?  What can you learn from Dagaz? 
Dagaz holds the energy of birth because it’s the transition from one space into another through a narrow passage and it holds the energy of death because it's a transition from one space to another through a narrow passage.
Does the light emerge from the darkness or does the darkness emerge from the light?  Or do both things happen?  How do you answer?