What does the term lattice refer to in the context of crystalline solids?

In the context of crystalline solids, the term "lattice" specifically describes the three-dimensional arrangement of points that represent the positions of the particles, such as atoms, ions, or molecules in the solid. This arrangement reflects the symmetry and repeatability that characterize the crystal structure, allowing for the formation of a solid with specific geometric shapes.

The lattice is crucial for determining various properties of the crystalline material, including its symmetry, density, and how it interacts with light and energy. Each point in a lattice corresponds to a repeating unit cell, which is the smallest portion of the lattice that, when repeated in three-dimensional space, creates the entire crystal structure.

This understanding is fundamental in fields like material science and solid-state physics, where the arrangement of particles within a crystal can significantly influence the material's properties such as conductivity, strength, and thermal expansion.