What is rensidity?

Answer 1

The spoiling of food due to its reaction with oxygen present in air is called rancidity.

Answer 2

It appears there may be a typo in your question. If you meant to ask about "residency," it refers to the state of living in a particular place, typically for a prolonged period of time. Residency can have legal implications, such as determining where an individual pays taxes, votes, and accesses certain services.