close in

UK: /kləʊz/

Collins Concise English Dictionary © HarperCollins Publishers::

close in / kləʊz/ verb (intr, adverb)

1. (of days) to become shorter with the approach of winter
2. followed by on or upon: to advance (on) so as to encircle or surround

WordReference Random House Unabridged Dictionary of American English © 2025

close-in  (klōs′in′), adj. 

1. near, as to a common center;
   adjacent, esp. to a city:
   The city is enveloping its close-in suburbs.
2. occurring or provided at close quarters:
   Fighter planes provided daring close-in air support.