Webster's Revised Unabridged Dictionary · 1913

Aaron's rod

Aaron's rod (âr"unz rod`)

[See Exodus vii. 9 and Numbers xvii. 8]

1.
(Architecture) A rod with one serpent twined around it, thus differing from the caduceus of Mercury, which has two.
2.
(Botany) A plant with a tall flowering stem; esp. the great mullein, or hag-taper, and the golden-rod.