Is there a word for suffocation by chest compression?
One term appears to be Mechanical / traumatic asphyxia
Mechanical / traumatic asphyxia: external compression of chest, preventing normal respiration. Forensics Asphyxia Author: Lindsey Harle, M.D.
Pathology Outlines
EDIT
I removed my reference to a Wikipedia article that used the term compressive asphyxia. It appears that the article may be corrupted. I'm no longer sure how widespread that particular term is.
Burking is the term applied to asphyxial deaths that result from someone sitting on another in a fashion that restricts breathing. The victim dies from asphyxia. This is a form of Mechanical Asphyxia, where the movement of the chest wall is restricted to the point that breathing isn't possible.
Source: Burking Still Lives After 200 Years | The Crime Fiction Writer's