Stay or cause to stay up-to-date with, as in He's keeping abreast of the latest weather reports, or Please keep me abreast of any change in his condition. This term alludes to the nautical sense of abreast, which describes ships keeping up with each other. [Late 1600s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.