What does the word deepen mean?

Usage examples for deepen

  1. It is always an artist's privilege to heighten or deepen natural effects. – Ways of Nature by John Burroughs
  2. He was as good as his word, for the first grey of dawn had hardly begun to deepen into pink when he was brought alongside, and climbed with some difficulty up the ladder. – The Green Flag by Arthur Conan Doyle
  3. The President's eyes glowed as he watched the grim lines deepen in Enoch's face. – The Enchanted Canyon by Honoré Willsie Morrow