To enclose around; to tighten or shrink; to collapse.(verb)
To catch up with in a chase; to near the end of a pursuit.(verb)
To near a goal or completion.(verb)
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Use "close in on" in a sentence
"(The Maids are reluctant, but Housekeeper commands them with her eyes to close in on Margaret, and they obey.) (Margaret backs away until she brings up against desk.)"
"He created a complex set of misdirections for the army unit that was trying to close in on his physical body; it would take them several hours to find him, far longer than necessary for the govern - ment to call them off."
"There was thus revealed not only the important fact that Lee was concentrating at Amelia Court House, but also a trustworthy basis for estimating his troops, so I sent word to Crook to strike up the railroad toward me, and to Merritt -- who, as I have said, had followed on the heels of the enemy -- to leave Mackenzie there and himself close in on Jettersville."