Ephemerida ephemerid • Ephemeridae · · · Info · Definitions · Characters · · Ephemerida · · Text Latin · · Script 10 · · Length Definitions · · · (noun) mayflies. Synonyms: Ephemeroptera, order Ephemeroptera, order Ephemerida. · · Noun Definition 1 Characters · · E latin capital letter e U+0045 a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 m latin small letter m U+006D p latin small letter p U+0070 r latin small letter r U+0072