bilateral (adj.)youdaoicibaDictYouDict[bilateral 词源字典]
"having two sides," 1775, from bi- + lateral. Related: Bilaterally.[bilateral etymology, bilateral origin, 英语词源]
pennateyoudaoicibaDictYouDict
"(Of a diatom) bilaterally symmetrical", Mid 19th century: from Latin pennatus 'feathered, winged', from penna 'feather'.