scutum vs sheath

scutum

noun
  • A scute. 

  • The kneecap. 

  • One of the two lower valves of the operculum of a barnacle. 

  • An oblong shield made of boards or wickerwork covered with leather, with sometimes an iron rim; carried chiefly by the heavily armed infantry of the Roman army. 

  • A shield-like protection, such as the scutum protecting the back of a hard tick (cf. alloscutum, conscutum) 

sheath

noun
  • A holster for a sword; a scabbard. 

  • The base of a leaf when sheathing or investing a branch or stem, as in grasses. 

  • A condom. 

  • The foreskin of certain animals (for example, dogs and horses). 

  • A tight-fitting dress. 

  • Anything that has a similar shape to a scabbard that is used to hold an object that is longer than it is wide. 

  • The insulating outer cover of an electrical cable. 

  • One of the elytra of an insect. 

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