The meaning of MDA

In 2004 an academic paper, broke down game design into 3 sections:

1. Mechanics: the workings of the game, the rules, the systems, progression, music, artwork etc..
2. Dynamics: how the player acts in response of those mechanics
3. Aesthetics: how the player feels by doing the actions

ex: Doom mechanic of ammo drops on killing enemies made the player push forward, which made them feel like Rambo.