Learn in the textbookProject Structure and Key Roles
DefinitionA stakeholder (ステークホルダ, also 利害関係者) is any person or organization that affects, or is affected by, how a project is run or how it turns out.
ExplanationPeople working inside the project are parties to it just as outside users and funders are, because their workload and evaluation shift with the outcome. Different positions bring different expectations of the project, and these sometimes clash. The project manager learns early who expects what and mediates between them.
AnalogyWith road works, the parties affected are not only the construction company but also neighbors forced to take detours and shops whose frontage is dug up.
Memory hookA stake is a wager or a share put in, and to have a stake in something means to have an interest in how it turns out. Read stakeholders as people with something riding on the result, and it is clear why insiders and outsiders both count.