Compared to an airplane:
PITCH is tipping forward and backwards to climb and dive, like dump and curl on a loader bucket.
YAW is pointing left or right, like angling a snowplow blade left and right.
ROLL is like waggling your wings, left down right goes up, right down left goes up, like if your snowplow could pivot in the center so when the left goes up, the right goes down. That would be called oscillation, I believe.
Now if you wanted both the left and the right of the pusher to be able to drop independantly, that would be called articulation, like articulated mowing decks that can handle undulating ground without scalping. I've never seen a pusher that could articulate.