An action item is a discrete task that must be accomplished, usually by a single individual or a small team or group.
Action items typically arise from meetings and should always be clearly documented. Most people overestimate how well they are likely to remember things. As a result, they may commit themselves to an action item, write a sketchy shorthand note about it and later wonder what it means. One way to prevent that scenario is ensuring that action items are expressed as full sentences. For example, “Create a draft of the request for proposal (RFP) for XYZ inc.” conveys a lot more information than simply “XYZ inc.”
It’s also important to ensure that all crucial details are included, such as task deadlines, the responsible party (if the action item is assigned to a team) and any consequent action items that are expected to arise from the original one. Action items arising from another are sometimes referred to as relay items.