cocoa vs rust

cocoa

noun
  • A light to medium brown colour. 

  • The dried and partially fermented fatty seeds of the cacao tree from which chocolate is made. 

  • A serving of this drink. 

  • An unsweetened brown powder made from roasted, ground cocoa beans, used in making chocolate, and in cooking. 

  • A hot drink made with milk, cocoa powder, and sugar. 

adj
  • Of a light to medium brown colour, like that of cocoa powder. 

rust

noun
  • A reddish-brown color. 

  • A similar substance based on another metal (usually with qualification, such as "copper rust"). 

  • A disease of plants caused by a reddish-brown fungus. 

  • Damage caused to stamps and album pages by a fungal infection. 

  • The deteriorated state of iron or steel as a result of moisture and oxidation. 

verb
  • To (cause to) degenerate in idleness; to make or become dull or impaired by inaction. 

  • To oxidize, especially of iron or steel. 

  • To cause to oxidize. 

  • To be affected with the parasitic fungus called rust. 

  • Of a black cat or its fur, to turn rust-coloured following long periods of exposure to sunlight. 

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