Two-feel — the jazz rhythm section playing "in two": the bass plays half notes (root on 1, fifth or approach note on 3) instead of walking, the drummer keeps the standard swing ride ("ding ding-a ding") with the hi-hat on 2 and 4, and the piano comps sparsely. It is how a band plays the head of a standard, the first chorus of a ballad at medium tempo, or the A sections before "opening up" into four.
The off-beat eighths here are swung — written at triplet positions (the "and" of 2 is at 1.667, not 1.5), which is where the ride's skip note and the piano's pushes actually land.
Listen for the space: with only two bass notes per bar the piano has room, and its pushes on the "and" of 2 and the "and" of 3 are what make the half-note bass feel like it is moving. Practice: play the bass part alone with the ride and keep the half notes long and dead centre; then add one piano chord per bar, then two. Compare freddie-green (four to the bar) and broken-time-comp for the same section playing in four.