noun
: one of the thin-walled fimbriated blood-filled evaginations more or less completely free from tracheae that are characteristic of certain chiefly aquatic insects and may be concerned with respiratory or osmotic activity
noun
: one of the thin-walled fimbriated blood-filled evaginations more or less completely free from tracheae that are characteristic of certain chiefly aquatic insects and may be concerned with respiratory or osmotic activity
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012