IPA: /nɒnˈfoʊkəl/
KK: /nɑnˈfoʊkəl/
Not related to or focused on a central point or main subject.
The study included nonfocal areas that were not the main focus of the research.
Nonfocal → It is formed from "non-" (meaning not) and "focal" (from Latin "focus", meaning center or hearth). The word "nonfocal" means not centered or not focused on a particular point.
Think of 'not' ('non-') being applied to something that is 'centered' ('focal') — that's why nonfocal means not focused on a specific center.