The following is an example of a "What/How/Why" definition:
Cosmology
WHAT: "1. A branch of metaphysics that deals with the nature of the universe 2 : a branch of astronomy that deals with the origin, structure, and space-time relationships of the universe" Definitions of related words:
Cosmos-- "1. a) an orderly harmonious systematic universe--compare chaos b) order, harmony 2. a complex orderly self-inclusive system"
Chaos-- "1 : chasm, abyss 2 a : a state of things in which chance is supreme; esp : the distinct foms -- compare cosmos b : a state of utter confusion."
HOW: through observation of the world and its phenomena which lead then to theories that explain why/how things work; theories can be "scientific" or in the form of myth/story/art; theories construct the world cosmologically--they put together the observed phenomena in a particular way, but then become "naturalized" and appear as if they are themselves observable fact/true/absolute.
WHY: to prevent chaos; because we seem to need an "orderly self- inclusive system" to protect from anomie, meaninglessness. [Or is even this observation the product of our cosmologies that explain the why in terms of what we think we need!?]
[Anomie -- "social instability reslting from a breakdown of standards and values; also : personal unrest, alientation and uncertainty that comes from a lack of purpose or ideals."]