A myriad is literally the number ten thousand; in that sense, the term is used almost exclusively in translations from Greek, Latin, or Chinese, or when talking about ancient Greek numbers. Wikipedia
Other sources say the same definition of Myriad that ancient sources always meant 10,000. Today the word can mean as little as a handful or bunch, to infinity. If however this word meant 10,000 when Jude wrote his book as Wikipedia says, it puts a quick end to the pretrib doctrine .
Jude 14 is the famous quote from the Enoch the 7th from Adam, we are told when Jesus returns He will return with 10,000s of His saints. We can only speculate how many millions of saints have gone before us and are ready and waiting to return with Christ for His bride.
I know that rubs the pretrib doctrine, but check out another verse. Paul is speaking of the bride being made ready here on Earth so she can be presentable to the Father, when Jesus comes with the rest of His saints 1 Thess. 3:12,13.
This parallels Rev. 19, and removes the confusion that comes with the pretrib doctrine that assumes the bride is already in heaven. The Word in Rev. 19 says, that she has made herself ready, and the location of where she has made herself ready is assumed. It’s a good thing we have the rest of the Word to remove those nasty assumptions.
The post-trib view doesn’t need myriad to mean what it does, but it is imperative to the pretrib that it doesn’t have a number. Best for the pretrib view to avoid 1 Thess. 3:13 altogether.
I attempted further research concerning the quote from Enoch. Not yet finding the exact quote, but fasinating book, prophesies fulfillment of the world’s events from beginning of time to the end. It also address the time segment of “weeks” that seem to stumble so many doctorates of theology concerning Daniel. It is interesting in chapter 100 how it tells us that God’s angels will protect His own in the coming time of Judgement.