a large number of something
myriad - countless
A ‘myriad’ is a very large number or a great variety of something. It is a formal word that is most commonly used in a professional context, especially with regards to expressing that a wide array of options are available. It is also common in written English, particularly in print media.
There are a myriad of options available to us. It’s just a case of putting a panel together to choose the right one.
Thanks to extensive investment in the area, a myriad of hotels, bars, and restaurants have opened up on the waterfront.
The politician deflected blame away from her own poor performance and claimed there were a myriad of other reasons why the scheme failed.