Dorian begins telling the story of meeting Sibyl Vane like this: "One evening about seven o'clock I determined to go out in search of some adventure. I felt that this gray, monstrous London of ours, with its myriads of people, its splendid sinners, and its sordid sins, as you once said, must have something in store for me. I fancied a thousand things."
What does "myriads" mean?