The word Trienial is misspelled against Triennial, meaning "Taking place every third year."
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Triennial has double "nn" is mispronounced as "n"
Remember double 'NN' in between the strings trie & ial which should not be misspelled with single 'N'
Wrong Spelling: trie-n-ial
Correct Spelling: trie-nn-ial
Find more wrongly spelled words of Triennial to spell it well.