Definition of "tripinnate" []

• Divided into pinnae that are subdivided into smaller, further subdivided leaflets or lobes, as in many ferns. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Stipes three to nine inches tall, blades one to three inches, triangular-ovate, pinnate at the summit, and tripinnate below."
• "A tripinnate form of this variety discovered at Concord, Mass., by Henry"
• "Fronds eight to eighteen inches long, lanceolate-oblong, tripinnate."