Twilight, golden hour and blue hour
Twilight is named by how far the sun is below the horizon. Civil twilight lasts until it is 6° below: there is enough light to be outdoors without lamps. Nautical twilight runs to 12°, when the horizon at sea fades. Astronomical twilight ends at 18°, when the sky is fully dark. Near midsummer at higher latitudes the sun never sinks that far, and the night stays in twilight.
Golden hour is the warm, low light with the sun between 4° below and 6° above the horizon; blue hour is the deep blue just before and after it, with the sun between 6° and 4° below. Photographers use these limits, though there is no official definition, and the light you actually see depends on the weather.