cloak vs covering

cloak

noun
  • A blanket-like covering, often metaphorical. 

  • A long outer garment worn over the shoulders covering the back; a cape, often with a hood. 

  • That which conceals; a disguise or pretext. 

  • A text replacement for an IRC user's hostname or IP address, making the user less identifiable. 

verb
  • To cover up, hide or conceal. 

  • To render or become invisible via futuristic technology. 

  • To cover as with a cloak. 

covering

noun
  • That which covers or conceals; a cover; something spread or laid over or wrapped about another. 

  • Action of the verb to cover. 

  • A continuous map onto a topological space X, 𝜋:E→X, such that there exists a discrete space D and for every x∈X an open neighborhood U⊂X, such that 𝜋⁻¹(U)= displaystyle bigsqcup _(d∈D)V_d and 𝜋|_(V_d):V_d→U is a homeomorphism for every d∈D. 

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