Software Architect's Handbook

Value objects

Unlike entities, value objects are objects that describe some characteristic or attribute, but have no concept of identity. They are defined by the values of their attributes and are immutable. If two objects have the same values assigned to their properties, they can be considered equal.

For example, if two objects that represent points on a graph using Cartesian coordinates have the same x and y values, they can be considered equal and would be modeled as a value object.