A short shot is the incomplete filling of a mold cavity which results in the production of an incomplete part.
If a part short shots, the plastic does not fill the cavity. The flow freezes off before the flow paths have completely filled.
To ensure the finished part is of good quality, the part must also be adequately packed with plastic. Therefore the question to ask is not only, “Will the part fill?” but also, “Can a good quality part be made?”