Zero In On

1. To aim precisely at a target. 2. To direct one's attention to or concentrate on something. 3. To converge on or close in on something.

Examples:

• They zeroed in on the last snipers.
• We must zero in on the exact combination of ingredients.
• The children zeroed in on the electric train display.

Origin: Sense 1 from c. 1940; senses 2 and 3 from mid-1900s