# Terminology#

## Grid Representation#

**Structured Grids**: Structured grids are defined by regular connectivity and topology,
typically forming a uniform pattern. They are represented using a multidimensional array, where each grid point has a predictable neighbor.
Below is an example of what a structured grid may look like.

**Unstructured Grids**: Unstructured grids do not follow a regular pattern, allowing for a flexible representation of complex geometries.
They are composed of various elements such as triangles, quadrilaterals, and other larger geometries, each of which are
made up of nodes and edges. Below is an example of an unstructured grid used in the dynamical core of a CAM-SE model.

**Node**: A point within a spherical grid, representing the vertices of the elements (such as the corners of triangles or quadrilaterals)

**Edge**: A segment that connects two nodes within a grid.

**Face**: An individual polygon that is defined by nodes connected by edges.

**Connectivity**: Connectivity describes how nodes, edges, and faces are interconnected within a grid.
It outlines the relationship between individual elements of the mesh, determining how they join together.

**Fill Value**: An arbitrary value used for representing undefined values in within connectivity variables when working
with fixed-size arrays.