"Heat content" refers to the amount of heat energy stored within a substance or system. It indicates how much heat is present or available for transfer or use. Full definition
Failure to include this aspect of ocean heat content changes the shape of the curve. (realclimate.org)
He is also correct that global heat content of the ocean is a huge part of warming or the lack thereof, but his next statement is not entirely correct. (climate-skeptic.com)
To answer this, we need to view observations of ocean heat content over the past 40 years. (skepticalscience.com)