close in
verb1
To enclose, lock up inside something.
2
To come or approach nearer to someone being pursued.
- The police had not yet caught the thieves, but were closing in.
- Keep refining your estimate, and you will gradually close in on the right answer.
3
To become closer, surround.
- Then we pass through Bebington station, and, entering a cutting, become aware of the usual signs of approach to an urban area—buildings closing in, an all-round increase in smokiness, and the application of brakes.1955 January, R. S. McNaught, “From the Severn to the Mersey by Great Western”, in Railway Magazine, page 21:
- Derived terms
- close in on