Wikipedia's page on cognitive load starts with
In cognitive psychology, cognitive load refers to the effort being used in the working memory. Cognitive load theory differentiates cognitive load into three types: intrinsic, extraneous, and germane. [...]
The page does not seem well written because it quickly gets to odd specifics like:
High cognitive load in the elderly has been shown to affect their center of balance.
Is that first quote a good definition or is too narrow? Is cognitive load really all about working memory?