Entry 1 sense Webster, 1913 Sea anemone /sē ăn'-ĭm-ōnˌ/ · Sea· a·nem·o·ne · IPA 01 Any one of numerous species of soft-bodied Anthozoa, belonging to the order Actinaria; an actinian. 1. Any one of numerous species of soft-bodied Anthozoa, belonging to the order Actinaria; an actinian.(Zool.)