I am not sure of the of 'Meta Description'. I look to the Hummingbird Algorithm for understanding their search / ranking queues today. As a thought exercise for understanding I view it as with actual verbalization with language usage. How is it spoke seeking answers as a complete thought with how to provide those answers as ranked.
In other words their algorithm is much more intuitive in a sense with its intelligence. It is not focused on singular keywords or simple phrases it is inclusive of the context of what is sought. However, there is more dependence on long-tailed keywords within that context.
They still run Panda and Penguin. But, I don't see those as much related directly to ranking as a search occurs. What I mean by that they do rank relational to their objective as a algorithm for a placement in a page, but the actual query leads rather than the queues themselves as keywords or phrases. Perhaps that should be qualified with if only a key world or simple phrase is searched they will be dependent on the ranking by Panda and/or Penguin. If a cognitive or sentence or near to is used then it will be by Hummingbird.
Perhaps I am off kilter and wrong altogether?