All 3 Uses

niche
in
The Count of Monte Cristo
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The Monte Pincio seemed a vast amphitheatre filled with spectators; the balconies of the two churches at the corner of the Via del Babuino and the Via di Ripetta were crammed; the steps even seemed a parti-colored sea, that was impelled towards the portico; every niche in the wall held its living statue.†
Chpt 35-36
Five corridors diverged like the rays of a star, and the walls, dug into niches, which were arranged one above the other in the shape of coffins, showed that they were at last in the catacombs.†
Chpt 37-38 *
These arcades opened on one side into the corridor where the count and Franz were, and on the other into a large square chamber, entirely surrounded by niches similar to those of which we have spoken.†
Chpt 37-38

Definitions:

(1) (niche as in: it is a niche product)
a special role, interest, or small market where someone or something fits especially well; or literally
(2) (niche as in: in a niche of the wall)
a small hollow space in a wall for a statue or decoration; or any shallow recess, cranny, or crevice
(3) (meaning too rare to warrant focus)
More rarely, niche can refer to a role for a species within an ecosystem.