Use Case Analysis
Use case analysis is the heart of UML (Unified Modelling Language) and it summarises how users of a system (Actors) can access various actions (Use Cases) the system provides to achieve a particular goal,
For more detail see Use Case Diagram Tutorial
Class Diagrams
The class diagram provides a design for the software and shows how the code will be structured into classes, each class containing methods and attributes
For more detail see Class Diagram Tutorial
Class Diagram Specifications
Each class, method and attribute can have detailed specifications and descriptions which can be generated as code comments
ERD Diagrams for Generating Databases
Class diagrams were developed from ERD (Entity-Relationship Diagrams) which were used to design database management systems. They define Entities which contain Attributes
For more detail see How to Design Relational Databases
Data Dictionaries
ERD Diagrams can generate the database using DBMS systems such as SQL Server or Oracle, and they can also generate documentation such as Data Dictionaries