It's the root of many English words, including:
* Sedentary: Sitting or inactive for long periods.
* Sediment: Matter that settles to the bottom of a liquid.
* Sedative: A substance that calms or soothes.
* Insidious: Proceeding in a gradual, subtle way, but with harmful effects.
While the original meaning of "sit" might seem simple, it underlies a wide range of concepts related to stillness, settling, and even gradual, often harmful, processes.