undulateyoudaoicibaDictYouDict[undulate 词源字典]
undulate: [17] Undulate goes back ultimately to Latin unda ‘wave’, source also of English inundate [17], redundant, and surround. This in turn was descended from the Indo-European base *ud-, which also produced Greek húdōr ‘water’ (source of the English prefix hydro-), and variants of which lie behind English vodka, water, and wet.
=> abound, inundate, redundant, sound, surround[undulate etymology, undulate origin, 英语词源]
undulate (v.)youdaoicibaDictYouDict
"to move in waves," 1660s, back-formation from undulation. Related: undulated, undulating.