capillary vs ductus

capillary

noun
  • A narrow tube. 

  • Any of the small blood vessels (from 5 to 10 micrometres/micrometers (μm) in diameter) that connect arteries to veins (They are the smallest blood vessels in the body: they convey blood between the arterioles and venules). 

adj
  • Of or pertaining to a narrow tube. 

  • Of, relating to, or caused by surface tension. 

  • Of or pertaining to hair. 

ductus

noun
  • a duct, tube or canal in the body 

  • a subtle reduction of weight towards the middle of the stroke of the letter 

  • the number of strokes that make up a written letter, and the direction, sequence and speed in which they are written (Compare graph; see also aspect.) 

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