Five-sided polygon (pentagon).

Anything related to the number five.

A group or set of five items/units.

An event involving five participants or elements.

**Five-part structure**: Composed of five distinct elements.

**Pentavalent**: Relating to a chemical with five valence electrons.

**Pentahedral geometry**: Shape characterized by five faces or surfaces.

**Pentameric formation**: Referring to a complex made up of five units.

**Fivefold symmetry**: Exhibiting symmetrical properties in groups of five.