Terreplaun or Terreplein: How To spell?

The word Terreplaun is misspelled against Terreplein, a noun meaning "The top, platform, or horizontal surface, of a rampart, on which the cannon are placed. See Illust. of Casemate."

Word contains consecutive vowels 'EI' in between alphabets terrepl & n is misspelled as 'AU'
Wrong Spelling:  terrepl-au-n 
Correct Spelling:  terrepl-ei-n 
Check more misspelled words of Terreplein to spell it correct.