an ornamental recess in a wall or the like, usually semicircular in plan and arched, as for a statue or other decorative object.

a place or position suitable or appropriate for a person or thing

to find one's niche in the business world.

a distinct segment of a market.

Ecology . the position or function of an organism in a community of plants and animals.

pertaining to or intended for a market niche; having specific appeal

niche advertising.

to place (something) in a niche.

noun

alcove , byplace , calling , compartment , corner , cranny * , cubbyhole * , hole , hollow , indentation , nook , opening , pigeonhole * , position , recess , slot , vocation , apse , cavity , cranny , cubbyhole , place , retreat , space , tabernacle