The term issue is a simple 5 letter word but it is one pf paramount importance to the project management team, the project management team leader, and in fact to any party in general. Specifically, the term issue refers to a distinct and a unique point or matter that current stands to be in discussion in some manner, or can also reefer to a specific point or matter than has been already discussed and it is determined is actually up for dispute due to an inability to reach a compromise or agreement of sorts. The term issue can also refer to the point or matter than may already have been discussed, but in fact has not as of yet been settled and as a result is up for discussion yet again. In these cases, in which discussion is lengthy and typically involves the presentation of multiple (and typically in most cases opposing) viewpoints on the issue. Often times, it is necessary for the project team leader or another independent arbiter to step in and make the final call of an issue appears irresolvable.
This term is defined in the 3rd and the 4th edition of the PMBOK.