Sentence:  <WSD>One</WSD> morning I had been driven to the precarious refuge afforded by the steps of the inn, after rejecting offers from the Celebrity to join him in a variety of amusements. But even here I was not free from interruption, for he was seated on a horse-block below me, playing with a fox terrier. 
Meaning of the word marked with <WSD> tags:  Of a period of time, being particular.