1. a recess in a wall, especially one that contains a statue
2. any similar recess, such as one in a rock face
3. a position particularly suitable for the person occupying it
4. (modifier) relating to or aimed at a small specialized group or market
5. (ecology) the role of a plant or animal within its community and habitat, which determines its activities, relationships with other organisms, etc.
6. (trans.) to place (a statue) in a niche; ensconce (oneself)