O

Objective - Something toward which work is to be directed, a strategic position to be attained, a purpose to be achieved, a result to be obtained, a product to be produced, or a service to be performed.

Opportunity - A risk that would have a positive effect on one or more project objectives.

Organizational Breakdown Structure - A hierarchical representation of the project organization, which illustrates the relationship between project activities and the organizational units that will perform those activities. 

Outcome - An end result or consequence of a process or project.