A set of project proposals, projects, programs, sub-portfolios and operations managed together to achieve an organisation's strategic objectives.
For instance, a company in the energy sector might have as business objective to "reduce carbon emissions". This portfolio could include sub-portfolios such as "improving efficiency of solar energy production" or projects such as "streamlining transport routes".
Defining portfolios allows project-rich organisations gain an overall perspective on their current and future projects and give priority access to resources to those projects that are most likely to help them achieve their strategic objectives.
see also: program(me), project portfolio management, enterprise project portfolio management related articles: an in-depth analysis of best practices for r&d and portfolio management with michael menke, planisware recognized as a leader in gartner's 2019 "magic quadrant for project portfolio management", best practices in resource planning and forecasting to improve portfolio management