v. phr. , informal To make certain; make sure; settle. Joe had a hard time selling his car, but he finally nailed the sale down when he got his friend Sam to give him $300. The New York Yankees nailed down the American League Championship when they beat the Red Sox 3 to 0 on September 15.
NAIL DOWN
Meaning of NAIL DOWN in English
American idioms English vocabulary. Английский словарь американских идиом. 2012