Last week, I posted Herbie Hancock's comments on playing "inside" and "outside" of the usual scale notes when playing jazz. Putting three or more notes together at once makes a chord, and there are few better at putting together chords than Herbie Hancock.
When jazz players are playing chords, they're comping -- "accompanying" the soloist or singer, or for pianists, the melody.
Many people listening to jazz focus on the soloists and singers, but next time, try to focus your ears on the comping -- usually a piano or guitar -- behind the lead player. You'll find a great new world of enjoyment in the layers there.
Listen to Herbie with the V.S.O.P. Quintet, or anything by Bill Evans. If you prefer guitar jazz, check out Joe Pass and Herb Ellis comping behind Oscar Peterson, or Barney Kessel's playing behind Billie Holiday on her "Songs for Distingue Lovers."
Wes Montgomery was amazing at everything he did, and he was a virtuoso comping as well as soloing.