(in a spider or other arachnid) each of a pair of respiratory organs composed of many fine lamellae. They are situated in the abdomen and have openings on the underside.
〔动〕书肺（指蛛形纲动物，如蝎和蜘蛛的呼吸器官，由一系列叶状薄瓣膜组成，位于腹部，下有开口）
Example sentencesExamples
A researcher at the University of Manchester has reported finding slit-like structures and book lungs on some eurypterid fossils.
Respiration takes place through the body surface, and/or by means of gills, tracheae, or book lungs.
Most spiders breathe through tracheae; some, like the wolf spiders, have both book lungs and tracheae.
Like spiders, they were terrestrial and respired through book lungs, and walked on eight legs.
Definition of book lung in US English:
book lung
noun
Zoology
(in a spider or other arachnid) each of a pair of respiratory organs composed of many fine leaves. They are situated in the abdomen and have openings on the underside.
〔动〕书肺（指蛛形纲动物，如蝎和蜘蛛的呼吸器官，由一系列叶状薄瓣膜组成，位于腹部，下有开口）
Example sentencesExamples
A researcher at the University of Manchester has reported finding slit-like structures and book lungs on some eurypterid fossils.
Most spiders breathe through tracheae; some, like the wolf spiders, have both book lungs and tracheae.
Like spiders, they were terrestrial and respired through book lungs, and walked on eight legs.
Respiration takes place through the body surface, and/or by means of gills, tracheae, or book lungs.