One of two varieties of head lettuce (the other being butterhead). It's commonly known as iceberg, which in truth is a variety of crisphead. Other varieties include Great Lakes, Imperial, Vanguard and Western. Crisphead lettuce comes in large round tightly packed heads of pale green leaves. Though crisp, succulent and wilt-resistant, all crispheads have a rather neutral flavor. Choose those that are heavy for their size with no signs of browning at the edges.
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.