n.
Function: transitive verb
Date: 1913
1 : to determine or adjust the zero of (as a rifle)
2 a : to concentrate firepower on the exact range of ― usually used with in b : to bring to bear on the exact range of a target ― usually used with in
intransitive verb
1 : to adjust fire on a specific target ― usually used with in
2 : to close in on or focus attention on an objective ― usually used with in <investigators are zero ing in on a suspect>