DOTS stands for “Data-Oriented Technology Stack”, which is a collection of Unity technology to include their Entity Component System framework, the Burst Compiler, and their Job system.

Each of these technologies have their own descriptions, but a very quick (and perhaps over simplified) explanation:

ECS is a framework where you have entities that themselves have one or more components, acted on by systems. The way these components are laid out in memory and acted upon by systems is typically more cache friendly then traditional game engine design with heap allocated GameObjects that are themselves a mess of pointers (Structs of Arrays vs Arrays of Structs)

Burst allows you to annotate functions, jobs and systems written in a subset of unmanaged C# that compiles to highly optimized instructions for better performance.

The job system allows you to schedule jobs with dependencies in a useful way that can help enable parallelism without manually having to deal with thread primitives. The jobs can also be burst’s themselves and used in a non-parallel manner if you don’t have something easily parallelizable.