Modern jazz is a style of jazz characterized by fast tempo, instrumental virtuosity, and improvisation based on the combination of harmonic structure and melody. This style of jazz ultimately became synonymous with bebop, as either category reached a certain final maturity in the 1960's.
I put that definition up there for others; while my definition is quite similar, it is unwavering. Anybody who doesn't like my definition can find another one, or write their own.
This definition indicates a style of jazz synonymous with "Be Bop"; that's what "Bird" invented with a little help from some friends. For the true connoisseurs of "Be Bop", "Birds" Bop is the only "Bop" that has withstood the test of time; his Bop sounds like music played at a fast pace, while others sounds like a lot of notes played real fast, and people accepted it as Bop.
In the formal definition, it states that "modern Jazz" reached it's maturity in the 60's, and that's "Koshure" with me. It doesn't have a cutoff date, like January 7, 1964, but I hope you get my drift. If you are a seasoned "aficionado", I'm sure you do.
Hopefully this post will cut down on a lot of confusion, but for some, everything adds confusion; consequently we will have to let them remain in their perpetual state of confusion.
After "modern jazz" reached it's final maturity, what followed was "Yankee Doodle stuck a feather in his hat, and called it macaroni". I figure it's good enough that we can almost define one segment of jazz, without defining all abstract music.
Presently I'm down loading my vinyl to the computer library, which is something that pays great dividends after a significant analog upgrade in the front end. The most welcome surprise is all the "brand new" old records; evidently, when I saw a new record of one of my favorite worn records, I bought it. This must have occurred when we changed from LP to CD, because for ages I didn't even have a cartridge, and therefore played no LP's. For the record, this stuff in no way compares to analog back in the day, when a BIC turntable and top of the line "Shure" or "Empire" cartridge was hot stuff.
I'm going to share with you what I just down loaded; "Bobby Hutcherson, San Francisco featuring Harold Land".
https://www.youtube.com/watch?v=cgXmbhkWkwkThis tune is representative of the entire album, it's a real winner;
Enjoy the music.