I was watching Heathers the other night, and I was chagrined to see that though the word “myriad” was misused in a suicide note, a teacher remarked that she was impressed to see that the student who was believed to have written it used it correctly. The number associated with said word is 10,000. You’d never say “a 10,000 of problems.”
I looked up the word, merely intending to glance at the definition I already knew just to validate my smug self-righteousness. As it transpired, I was left flabbergasted (the following is from Merriam-Webster):
Recent criticism of the use of myriad as a noun, both in the plural form myriads and in the phrase a myriad of, seems to reflect a mistaken belief that the word was originally and is still properly only an adjective. As the entries here show, however, the noun is in fact the older form, dating to the 16th century. The noun myriad has appeared in the works of such writers as Milton (plural myriads) and Thoreau (a myriad of), and it continues to occur frequently in reputable English. There is no reason to avoid it.
I am shaken and humbled.