“What is this? cheese!”
Its difficult to translate the concept of Qi or Chi into english mainly because like with most things in chinese medicine it was developed in china, thousands of years ago, from a Chinese medical point of view which is full of associations and ideas that we in the west are not familiar with.
Qi is pronounced βcheeβ (just like in the word cheese) and you can interpret it as the vital life force (or breaths) that runs through every living body, which is responsible for that constant movement from yin to yang and from yang to yin.
Qi is the basis of all phenomena in the universe, in the human body it manifests in physical and spiritual capacities as both function and energy. It is responsible for all the activities that occur in the human body, from digesting food and immune functions to blood circulation and mental activities.