a lemon-scented plant, Collinsonia canadensis, of eastern North America, having small yellow flowers.
Before X Was X: The Dark Horse Story Of The 24th LetterSince its inception, the letter X has struggled to establish its own identity, so it may be no coincidence that X is commonly used to represent the unknown in both language and mathematics. But, how was it created?
Origin of horse balm
An Americanism dating back to 1780–90
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for horse balm
Only a few days since, while out on a drive, I passed a luxuriant clump of the plant known as "horse-balm."
Horse-balm (Collinsonia), its singular shape, 136;manner of bee's approach to, 138.