Sentence:  And we have more sure the prophetic word; to which ye do well that ye take heed, as to a lamp shining in a dark place, until the day dawn, and the <WSD>daystar</WSD> arise in your hearts; <!--other translations have "Morning Star", so it seems this is the intended usage--> 
Meaning of the word marked with <WSD> tags:  The morning star; the planet Venus.