The word Sidereil is misspelled against Sidereal, meaning "Pertaining to stars or constellations."
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Sidereal has vowels 'ea' together mispronounced as 'ei'
Word contains consecutive vowels 'EA' in between alphabets sider & l is misspelled as 'EI'
Wrong Spelling:  sider-ei-l 
Correct Spelling:  sider-ea-l 
Find more wrongly spelled words of Sidereal to spell it well.