thefreedictionary.com is only one of many dictionaries that use "myriad of" in their examples. Here are some more: http://www.yourdictionary.com/myriad http://w

thefreedictionary.com is only one of many dictionaries that use "myriad of" in their examples. Here are some more: http://www.yourdictionary.com/myriad http://www.yourdictionary.com/myriad A quick Google Ngram search supports the claims from thefreedictionary, that "a myriad" or "myriads" was used first and that "myriad" as an adjective was only used later: https://books.google.com/ngrams/graph?content=%28myriad_NOUN%2Bmyriads_NOUN%29%2Cmyriad_ADJ&year_start=1600&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2C%28myriad_NOUN%20%2B%20myriads_NOUN%29%3B%2Cc0%3B.t1%3B%2Cmyriad_ADJ%3B%2Cc0 https://books.google.com/ngrams/graph?content=%28myriad_NOUN... It looks like "myriad of" has been correct in the past and is still used widely.