1. The section of flesh on the body of a person or an animal between the last rib and the hip; the side.
2. A cut of meat from the flank of an animal.
3. A lateral part or side: the flank of a mountain.
a. The right or left side of a military formation: an attack on both flanks.
b. The right or left side of a bastion.
tr.v. flanked, flank·ing, flanks
1. To protect or guard the flank of.
2. To menace or attack the flank of.
3. To be placed or situated at the flank or side of: Two stone lions flanked the entrance.
4. To put (something) on each side of: flanked the driveway with tall shrubs.
[Middle English, from Old English flanc, from Old French flanc, of Germanic origin.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2019 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.