What does the word grotto mean?

Usage examples for grotto

  1. We sat down in a charming grotto, and began styling each other papa and daughter, and allowing ourselves liberties which threatened to lead to danger. – The Memoires of Casanova, Complete The Rare Unabridged London Edition Of 1894, plus An Unpublished Chapter of History, By Arthur Symons by Jacques Casanova de Seingalt
  2. The grotto constructed by the poet may still be seen near the railway station at Ware. – Hertfordshire by Herbert W Tompkins