Definitions for heavy cream
Random House Webster's College Dictionary
thick cream having a high percentage of butterfat.
contains more than 36% butterfat
A rich cream, at least 36 percent of which is milkfat.
Pasteurized cream at least 36 percent of which is milkfat, optionally homogenized, and optionally containing added flavor, nutritive sweetener, emulsifier or stabilizer.
Origin: The standard of identity is from 21 CFR §131.150.