: exhibiting or producing a condition in which people or things are closely united
In chemistry, COHESION describes the physical property of a substance whose intermolecular attraction acts to unite said involved molecules. There is probably an extremely more successful way to paraphrase that concept, but I'm sticking with the above. A lazy and yet prime example of chemical cohesion: water.
In writing, COHESION is form, structure, flow. As I write, I feel fairly responsible for the COHESION of the words I thoughtfully throw around. This is a fallacy. It is the form that holds the words together, not me. Eventually I will crumble, and for the words remain in their present arrangement they must exist in a solid form outside the temporary and imagined grip of my hands.
COHESIVE is a word used to draw attention away from the trees and to the forest. The big picture. It is a concept without which form would be nothing but disparate pieces thrown into a moldy cardboard box.
This box, of course, may become COHESIVE if one were to scribble something on its side like: JIM'S OLD BELONGINGS - NEVER PICKED UP.
There is little COHESION, in case you haven't noticed, in the writing of this blog. It is held together by the (not so) random forces of Merriam-Webster.