Webster’s Revised Unabridged Dictionary · 1913
Ecthoreum
Ec′tho·re′um, n.; pl. Ecthorea (#). [NL., fr. Gr. ἐκθρώσκειν to leap out; εκ out + θρώσκειν, θορεῖν, to leap, dart.] (Zoöl.) The slender, hollow thread of a nettling cell or cnida. See Nettling cell. [Written also ecthoræum.]