A simple set can be represented mathematically as

• {x1, x2, x3, x4, x5}

(English)

The most common lexical relation of this type in English is a synonym set. A synonym set consists of lexical units which share all or most of their core semantic components.

Here are some examples of synonym sets:

• {assembly, gathering, meeting}
• {just, equitable, lawful, fair}
• {happy, joyful, glad}