A test for sugar syrup desribing the point at which a drop of boiling syrup immersed in cold water forms a rigid ball. Though the ball is hard, it will still be somewhat pliable. On a candy thermometer, the hard-ball stage is between 250° and 265°F.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.