Webster's Revised Unabridged Dictionary · 1913

Dipnoi

Dipnoi , noun, plural

[New Latin, from Greek {not transcribed} with two breathing apertures; di- = di`s- twice + {not transcribed} breath.]

(Zoology) A group of ganoid fishes, including the living genera Ceratodus and Lepidosiren, which present the closest approximation to the Amphibia. The air bladder acts as a lung, and the nostrils open inside the mouth. See Ceratodus, and Illustration in Appendix.