The word pervasive means existing in every part of something. It is an adjective used in both fiction and nonfiction writing.
The word pervasive originates from the root word pervade. Pervade, in turn, originates from the Latin word pervadere, meaning to go through. The first known use of pervasive was around 1750. It rhymes with the word abrasive.
Pervasive can also mean spreading through all the parts of something. The Internet has a pervasive influence around the world, for example. The word all-pervading is similar to pervasive and means to have an effect through all the parts of something.