Remember or consider on reflection. For example, Come to think of it, I've got to send in my order now, or I was going to lend him a saw, but come to think of it, he already has one. [First half of 1800s]

The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Company. All rights reserved.