1. A thin straight piece or bar of material, such as metal or wood, often having a particular function or use, as:
a. A fishing rod.
b. A piston rod.
c. An often expandable horizontal bar, especially of metal, used to suspend household items such as curtains or towels.
d. A leveling rod.
e. A lightning rod.
f. A divining rod.
g. A measuring stick.
h. One of the horizontal elements in a truss system underneath a rail car, especially a freight car.
2. A shoot or stem cut from or growing as part of a woody plant.
a. A stick or bundle of sticks or switches used to give punishment by whipping.
b. Punishment; correction.
a. A scepter, staff, or wand symbolizing power or authority.
b. Power or dominion, especially of a tyrannical nature: "under the rod of a cruel slavery" (John Henry Newman).
5. Abbr. rd
a. A linear measure equal to 5.5 yards or 16.5 feet (5.03 meters). Also called pole2.
b. The square of this measure, equal to 30.25 square yards or 272.25 square feet (25.30 square meters).
6. Anatomy Any of various rod-shaped cells in the retina that respond to dim light. Also called rod cell.
7. Microbiology An elongated bacterium; a bacillus.
8. Slang A pistol or revolver.
9. Vulgar Slang A penis, especially when erect.
[Middle English rodd, from Old English.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.