Myriad

1. имя существительное 1) несметное число, мириады 2) [устаревшее] десять тысяч 2. прилагательное [поэтическое] 1) бессчётный, бесчисленный, неисчислимый, несметный Синоним(ы): innumerable, countless 2) разнообразный, разнородный

Большой англо-русский словарь

Myriad

I. noun Etymology: Greek myriad-, myrias, from myrioi countless, ten thousand 1. ten thousand 2. a great number Example: a myriad of ideas Usage: 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. II. adjective 1. innumerable Example: those myriad problems; also both numerous and diverse Example: myriad topics 2. having innumerable aspects or elements Example: the myriad activity of the new land — Meridel Le Sueur

Merriam-Webster's Collegiate Dictionary