1. plural of focus; the central points of attention, activity, or interest
2. plural of focus; in geometry, two fixed points used to define an ellipse
Usage: mathematics
3. plural of focus; in optics, points where light rays converge or appear to diverge from
Usage: physics

Examples

• The research project had two main foci: climate change and renewable energy.
• The teacher identified several foci for the semester’s curriculum.
• In mathematics class, we learned how to locate the foci of an ellipse.
• The telescope’s mirrors direct light to specific foci for clear imaging.
• The company’s strategic foci include innovation and customer service.
• Students struggled to understand how the foci determine an ellipse’s shape.
• The conference had multiple foci ranging from technology to education.