What does the word allegro mean?

Usage examples for allegro

  1. It is not of the same character as the preceding work, but resembles rather the Allegro of a Sonata. – Johann Sebastian Bach by Johann Nikolaus Forkel and Charles Sanford Terry
  2. This introductory passage is marked, " Sostenuto assai," followed by the main movement marked, " Allegro ma non troppo." – Memories of a Musical Life by William Mason