The words and names below can be changed into new words by the insertion of the same three letters, in the same, consecutive order. The three letters form a word in their own right. What are the three letters and what are the new words?

TAN
HEY
CHER
STING
BERING
COUCHES

Answers:

The letters are ART:

TARTAN
HEARTY
CHARTER
STARTING
BARTERING
CARTOUCHES

Credit:
NPR Weekend Edition Sunday Puzzle
April 9, 2017
Will Shortz