A recent question in the early stages asked what the period when it was light before the sun came up was called and the answer, from a number of girls names, was given as 'Dawn'.
I understood dawn to be when the sun first appeared above the horizon and the period of light before that to be called 'Prime'. In fact I said 'prime' before the four answers even showed. you lose a star. Well they do disappear at dawn, or prime :)