zero in on

zero in on  {v.}
1. To adjust a gun so that it will exactly hit (a target); aim at.
Big guns were zeroed in on the enemy fort.
American missiles have been zeroed in on certain targets, to be fired if necessary.
2.  {slang}
To give your full attention to.
The Senate zeroed in on the Latin-American problems.
Let's zero in on grammar tonight.
Categories: {slang} {v.}