What's the distinction between "planetary formation mechanisms" and "gravitational collapse"? As I was curious about the exact identical comment to my title here: https://astronomy.stackexchange.com/a/16135/10102

And as it seems no one asked it yet, I'm simply interested in the difference of the both, so:

What's the distinction between "planetary formation mechanisms" and "gravitational collapse"?
"Gravitational collapse" is not the generally used name of any planet formation model it simply refers to the collapse of a cloud of gas or collection of objects under the influence of their mutual gravity. "Planetary formation mechanisms" simply refers to mechanisms which form planets, all of which involve the mutual gravitational attraction of the planetary components at some phase.

In the context of the answer you refer to, there "gravitational collapse" refers to where a small object (like a brown dwarf) forms through the same direct collapse and fragmentation process that forms stars.

Planets on the other hand are thought to form in the disc that is inevitably created around a protostar during the star formation process. This might be through something called gas disc instability, or the more likely model at present is something known as the core accretion model.