How we change what others think, feel, believe and do
Merism is referencing something by listing its constituent parts or multiple descriptors.
Flesh and bone (the body).
Search every nook and cranny (= look everywhere).
Sun, sea and sand (a holiday destination).
Describing something by just naming it is can be quite bland. When you want to be brief, then a fuller description is also less than satisfactory. Merism fills the gap, giving a very brief and possibly creative description.
By listing parts, the description is lengthened, thus drawing attention to the subject. In particular, attention is drawn to the parts lists (which may or may not be important).
Common merisms are found in the English language where they are used as a form of Metaphor.
Merism is also often found in legal documents where multiple very similar words are used to ensure a subject is fully covered ('last will and testament').
Classification: Reference, Amplification
And the big