keyhole vs niche

keyhole

noun
  • A mortise for a key or cotter. 

  • A gravitational keyhole. 

  • Any small opening resembling the hole for a key in shape or function. 

  • A hole or excavation in beams intended to be joined together, to receive the key that fastens them. 

  • A transient column of vapor or plasma formed when using high energy beams, such as lasers, for welding or cutting. 

  • The free-throw lane together with the circle surrounding the free-throw line; key. 

  • The hole in a lock where the key is inserted and turns. 

  • A circle cut out of a garment as a decorative effect, typically at the front or back neckline of a dress. 

  • A welding method in which a hole forms in the surface immediately ahead of the puddle in the direction of welding. The hole is filled as the weld progresses. 

verb
  • To strike a target after wobbling in flight so that the long axis of the bullet does not follow the line of flight, typically due to insufficient spin resulting from the rifling in the barrel. 

niche

noun
  • Specifically, a cremation niche; a columbarium. 

  • Any position of opportunity for which one is well-suited, such as a particular market in business. 

  • A cavity, hollow, or recess, generally within the thickness of a wall, for a statue, bust, or other erect ornament. 

  • Any similar position, literal or figurative. 

  • A function within an ecological system to which an organism is especially suited. 

  • An arrow woven into a prayer rug pointing in the direction of qibla. 

adj
  • Pertaining to or intended for a market niche; having specific appeal. 

verb
  • To specialize in a niche, or particular narrow section of the market. 

  • To place in a niche. 

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