The tangible output from a task. Examples are:
In a project environment it is recognised good practice that all tasks should have deliverables. You can argue that tasks with no physical outcome are of questionable value.
An example of a non-deliverable is:
A software engineer provides a verbal critique of a junior programmer's code.
In this case the deliverable from the code review task could have been a code inspection report. As nothing was physically produced the task had no deliverable.
See also: management by deliverables.