planarian Planaria • Planarida · · · Info · Definitions · Synonyms · Characters · · planarian · · Text Latin · · Script 9 · · Length Definitions · · · (noun) free-swimming mostly freshwater flatworms; popular in laboratory studies for the ability to regenerate lost parts. Synonyms: planaria. · · Noun Definition 1 Synonyms · · · planaria · · Synonym 1 Characters · · a latin small letter a U+0061 i latin small letter i U+0069 l latin small letter l U+006C n latin small letter n U+006E p latin small letter p U+0070 r latin small letter r U+0072