Green seaweed that's dried and used as seasoning; it's an abundant source of iron. Ao nori is the flaked version, whereas ao noriko is powdered. Both are available in small bottles in Asian markets.
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.