- The large tuberous root of a kind of milkweed (Asclepias tuberosa), used as a remedy for pleuritic and other diseases.
- The plant itself, which has deep orange-coloured flowers; butterfly weed.
Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
(See the entry for pleurisy root in Webster’s Revised Unabridged Dictionary, G. & C. Merriam, 1913.)