ecru vs horse chestnut

ecru

noun

  • A beige colour. 

adj

  • Of a beige colour. 

horse chestnut

noun

  • The large nutlike seed of these trees. 

  • Any of several tree species of genus Aesculus, especially Aesculus hippocastanum, common in temperate northern hemisphere. 

How often have the words ecru and horse chestnut occurred in a corpus of books? (source: Google Ngram Viewer )