In addition to Chris’ explanation, the term task is overloaded in the Camunda and BPMN context. It refers to a task in the BPMN 2.0 context (aka a design time unit of work that is/cannot broken down further => service task, human task, send task, etc.) as well as a task in the tasklist (aka a runtime unit of work that needs to be completed by a human).
Cheers,
Thorben