OsteichthyesPronunciation: /ˌɒstɪˈɪkθiːz/Definition of Osteichthyes noun Zoology a class of fishes that includes those with a bony skeleton. Compare with Chondrichthyes.Origin:modern Latin (plural), from Greek osteon 'bone' + ikhthus 'fish'Osteichthyes in other Oxford dictionaries Definition of Osteichthyes in the US English dictionary