Meaning of “niche” - Learner’s Dictionary

niche

noun [ C ] uk us /niːʃ/ US  /nɪtʃ/
ACTIVITY

a job or activity that is very suitable for someone:

After years of job dissatisfaction, he's at last found his niche in financial services.
HOLE

a hollow space cut into a wall

(Definition of “niche” from the Cambridge Learner’s Dictionary © Cambridge University Press)