Granularity (also called graininess), the condition of existing in granules or

grains A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legume ...

, refers to the extent to which a material or

system A system is a group of Interaction, interacting or interrelated elements that act according to a set of rules to form a unified whole. A system, surrounded and influenced by its environment (systems), environment, is described by its boundaries, ...

is composed of distinguishable pieces. It can either refer to the extent to which a larger entity is subdivided, or the extent to which groups of smaller indistinguishable entities have joined together to become larger distinguishable entities.

Precision and ambiguity

Coarse-grained materials or systems have fewer, larger discrete components than fine-grained materials or systems. * A coarse-grained description of a system regards large subcomponents. * A fine-grained description regards smaller components of which the larger ones are composed. The concepts granularity, coarseness, and fineness are relative; and are used when comparing systems or descriptions of systems. An example of increasingly fine granularity: a list of nations in the

United Nations The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...

, a list of all states/provinces in those nations, a list of all cities in those states, etc. Note that, although the modifying terms, ''fine'' and ''coarse'' are used consistently across all fields, the term ''granularity'' is not. * In photography: ''more granular''

photographic film Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin photographic emulsion, emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of th ...

has fewer and larger chemical "grains" * In food industry: ''more granular'' sugar has fewer and larger grains.

Physics

A ''fine-grained'' description of a system is a detailed, exhaustive, low-level model of it. A ''coarse-grained'' description is a model where some of this fine detail has been smoothed over or averaged out. The replacement of a fine-grained description with a lower-resolution coarse-grained model is called ''coarse-graining''. (See for example the second law of thermodynamics)

Molecular dynamics

molecular dynamics Molecular dynamics (MD) is a computer simulation method for analyzing the physical movements of atoms and molecules. The atoms and molecules are allowed to interact fo