| No | Word | Definition |
| 1 | Domain | A set of values that define the value range for an attribute. |
| 2 | Attribute | The basic unit in a relation (table) definition. Each attribute has a domain associated with it. |
| 3 | Relation Schema (Table Schema) |
Defines the structure of a relation (table) which consists of a set of attributes and an association between each attribute and its domain |
| 4 | Relational Database Schema |
A collection of relation (table) schemas. |
| 5 | Tuple (record/row) | A list of values with each value being an element in a domain or NULL. A tuple represent a record or row in a table (relation). |
| 6 | Relation (Table) | An instance of a relation schema which is composed of a set of tuples. |
| 7 | Database | A collection of relations (tables). |