🧩 Building Blocks of a Shared Language
On the previous page, we saw that the heart of Domain-Driven Design (DDD) is aligning software with the language of the business.
But how do we actually do that?
How do we make “shared language” more than just good intentions?
DDD gives us a small set of building blocks that make the language concrete.
Ubiquitous Language​
A fancy term for a simple idea:
Everyone — business, developers, product — uses the same words in the same way.
- No more “Order” meaning one thing to sales and another to fulfillment.
- No more translating between documents, code, and conversations.
- The model is the language, and the language is the model.
Entities and Value Objects​
When modeling the business, not all things are alike.
- Some things have identity — they matter because of who they are (e.g. a specific customer account).
- Some things matter only by their attributes — if the values are the same, they’re interchangeable (e.g. a shipping address).
Distinguishing between these keeps the model honest and avoids muddle.
Aggregates​
Business rules don’t just apply to individual objects — they often apply to clusters of things that must be kept consistent.
An Aggregate defines that cluster.
It says: when we make changes here, these rules must always hold true.
This keeps complexity from spilling everywhere and makes the system more predictable.
Why These Blocks Matter​
These aren’t just abstractions for architects.
They are tools for clarity:
- âś… They force precise conversations about what things mean.
- âś… They ensure the model reflects real business rules.
- âś… They keep the code and the business language in sync.
In short: The building blocks of DDD turn shared language into working software models.
They give teams the confidence that when they say “Order,” they all mean the same thing — and the system enforces it too.
👉 Next, we’ll zoom out to the bigger picture: how to handle complexity at scale with Boundaries and Relationships.