"wild iris," c. 1000, from Latin gladiolus "wild iris, sword-lily," literally "small sword," diminutive of gladius "sword" (see gladiator); the plant so called by Pliny in reference to its sword-shaped leaves. The Old English form of the word was gladdon. Form gladiol is attested from mid-15c.; the modern use perhaps represents a 1560s reborrowing from Latin.
updated on March 09, 2015