noun

• (architecture) A cavity, hollow, or recess, generally within the thickness of a wall, for a statue, bust, or other erect ornament.
  "On the margin of this long tract, are abundance of shrines and images, defended from the injuries of the weather by niches of stone wherein they are placed."
• (ecology) A function within an ecological system to which an organism is especially suited.
• (by extension) Any position of opportunity for which one is well-suited, such as a particular market in business.
  "Whitney, mother of Xavier, is a real estate titan who, along with her British husband, has found her niche selling luxurious underground bunkers to wealthy clients looking for a safe space to hunker down in the event of a climate apocalypse."
• (Islam) An arrow woven into a prayer rug pointing in the direction of qibla.

verb

• (transitive) To place in a niche.
  "a niched vase"
• (transitive, marketing) To specialize in a niche, or particular narrow section of the market.
  "Product differentiation will be mostly limited to market niching and fashion."