Also, into circulation. In business or social life, especially after a period of absence. For example, After a month in the hospital Bill was eager to get back in circulation. The antonym is out of circulation, as in Since we had twins we've been out of circulation, but we're hoping to get out more often soon. These expressions, dating from the first half of the 1900s, employ circulation in the sense of “making the rounds among people,” a usage dating from the 1600s.