PinnipediaPronunciation: /ˌpɪnɪˈpiːdɪə/Definition of Pinnipedia noun Zoology an order of carnivorous aquatic mammals which comprises the seals, sea lions, and walrus. They are distinguished by their flipper-like limbs. Order Pinnipedia: three families Origin:modern Latin (plural), from Latin pinna 'wing, fin' + pes, ped- footPinnipedia in other Oxford dictionaries Definition of Pinnipedia in the US English dictionary