Sentence:  Imogen:...Pr'ythee, speak, / How many score of miles may we well ride / 'Twixt hour and hour / Pisanio: One score, 'twixt <WSD>sun</WSD> and <WSD>sun</WSD>, / Madam, 's enough for you; and too much too. / Imogen: Why, one that rode to his execution, man, / Could never go so slow. 
Meaning of the word marked with <WSD> tags:  Sunrise or sunset.