Thrader or Threader: How To spell?

The word Thrader is misspelled against Threader, a noun meaning "A device for assisting in threading a needle."

Threader has vowels 'ea' together mispronounced as 'a'
Word contains consecutive vowels 'EA' in between alphabets thr & der is misspelled as 'A'
Wrong Spelling:  thr-a-der 
Correct Spelling:  thr-ea-der 
Explore spell check of Threader to spell without errors.

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