In Warhammer: the Old World, templates are used to represent the effect of certain weapons:

Blast Templates

A blast template is a round template 3" or 5" in diameter.

Flame Templates

A flame template is a teardrop-shaped template, approximately 8" in length.

These templates are used to determine which models are hit by an attack that has an area of effect or blast radius. If an attack uses a template, the rules will explain how to position it, and how it might scatter.