aqua vs blue-gray

aqua

adj
  • Of a greenish-blue colour. 

noun
  • A shade of colour, usually a mix of blue and green similar to the colour turquoise. 

  • The compound water. 

blue-gray

adj
  • Of a bluish grey color. 

How often have the words aqua and blue-gray occurred in a corpus of books? (source: Google Ngram Viewer )