The regions within a ferromagnetic material called domains are said to act like:

1. Domains explain how a whole piece of iron becomes magnetic. 2. Ferromagnetic materials contain magnetic domains that are themselves magnets. 3. The regions within the material called domains act like small bar magnets. 4. Aligning them makes the whole object magnetic. _Source: OpenStax College Physics for AP Courses 2e (CC BY 4.0), Ch 22 'Magnetism', sections 22.1-22.11_