meter is running, the
Costs or other consequences are accumulating, as in We'd better come to a decision soon, for the meter is running. This metaphoric expression alludes to the fare mounting up on a taxi meter. [Late 1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.